Devices and systems for thrombus treatment

ABSTRACT

A thrombus treatment device includes a support wire, a body frame portion that is disposed about an axis defined by the support wire, one or more tethers that each have a first end and a second end, and a filter element extending from the body frame portion. Each of the one or more tethers is attached at its first end to the body frame portion, and at its second end to a collar that couples the second end of each of the multiple tethers to the support wire. When the collar is positioned substantially within a region interior of the body frame portion, a rotational actuation of the support wire causes a swiveling motion of the one or more tethers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application and claims priority toU.S. application Ser. No. 14/935,833 filed Nov. 9, 2015, which claimspriority to U.S. application Ser. No. 13/802,428 filed Mar. 13, 2013,now U.S. Pat. No. 9,204,887, issued on Dec. 8, 2015, which claimspriority to U.S. Provisional Application No. 61/683,043, filed Aug. 14,2012. The disclosures of the prior applications are considered part ofand are incorporated by reference in the disclosure of this application.This application also incorporates by reference the disclosure of U.S.Pat. No. 9,308,007 filed on Mar. 13, 2013 entitled, “DEVICES AND SYSTEMSFOR THROMBUS TREATMENT.”

TECHNICAL FIELD

This disclosure relates to devices, systems, and methods for treatmentof thrombus.

BACKGROUND

Blood clot formation, or “thrombosis,” is a basis of a number of seriousdiseases, such as ischemic stroke, myocardial infarction (heart attack),and deep vein thrombosis (DVT). Blood clots, or “thrombi,” form insideblood vessels and obstruct the flow of blood through the circulatorysystem, thereby depriving tissue and organs of oxygen. In the case of astroke, for instance, when blood flow to the brain is obstructed forlonger than a few seconds, brain cells can die and permanentneurological damage can result.

Thrombi can be treated (reduced or eliminated) by inducing thrombolysis.Thrombolysis is the dissolving, or “lysis,” of a thrombus. Thrombolysiscan sometimes be induced pharmacologically, such as by administering atissue plasminogen activator drug (tPA), the most common thrombolyticagent. Thrombolytic agents (commonly called “clot-busting drugs”) can beadministered via an intravenous line or using a catheter to deliver themproximally to the thrombus. However, thrombolysis by administration ofclot-busting drugs has its limitations. For example, to be successful,the clot-busting drugs should be administered within three (3) hours ofan acute ischemic stroke, and preferably within two (2) hours. Further,patients who use blood-thinning medications, and certain othermedications, are usually not candidates for pharmacologicalthrombolysis. And of those patients receiving the treatment, it isunsuccessful in dissolving thrombi in approximately 25% of patients.

In view of the limitations of pharmacologically induced thrombolysis,various medical devices for surgically removing thrombi have beendeveloped. The procedure for surgically removing thrombi is generallyknown as a “thrombectomy.” In thrombectomy treatments, a catheter systemis typically used to deliver a device to the thrombus. The device canbe, for example, an aspiration catheter. Aspiration catheters canperform a thrombectomy by suctioning the thrombus out of the bloodvessel. Other thrombectomy procedures use a mechanical device tophysically entangle with a thrombus, and to remove the thrombus as thedevice is removed from the blood vessel. Various types of mechanicaldevices, such as wires, corkscrew-like coils, bristles, and baskets havebeen employed to entangle with thrombi.

Some traditional thrombectomy devices can cause damage to blood vesselwalls. In addition, some traditional thrombectomy devices can be proneto generating thrombotic fragments that become emboli when they travelwithin the bloodstream. Emboli can become lodged in arteries, veins,arterioles, and capillaries, and can block the blood supply to vitalorgans such as the brain or heart. Emboli in the bloodstream can belife-threatening. In the case of DVT treatment, dislodged thromboembolican travel to the lungs, resulting in a pulmonary embolism, which can befatal.

SUMMARY

This specification describes devices, systems, and processes fortreatment of thrombi. In brief, various embodiments are disclosed formechanically restoring a blood-flow path, facilitating lysis by bloodflow, withdrawing thrombotic material, and capturing thromboticfragments in a filter device. Additionally, devices, systems, andprocesses for maceration, aspiration and other adjunct processes aredisclosed.

In one general aspect, a thrombus treatment device is provided. Thethrombus treatment device includes a support wire; a body frame portionthat is disposed about an axis defined by the support wire, wherein alongitudinal length of the body frame portion is at least two times aslong as an outer diameter of the body frame portion; a tether portionthat includes one or more tethers that extend from the body frameportion to a collar that is coupled to the support wire; and a filterportion that extends from the body frame portion.

In various implementations, the longitudinal length of the body frameportion may be at least three times as long as the outer diameter of thebody frame portion. The longitudinal length of the body frame portionmay be at least four times as long as the outer diameter of the bodyframe portion. The longitudinal length of the body frame portion may beat least five times as long as the outer diameter of the body frameportion. A longitudinal length of the filter portion may be less than orequal to one-half of the longitudinal length of the body frame portion.The one or more tethers may be adapted to evert to a configurationwherein the one or more tethers are substantially within an area definedby the body frame portion. The one or more tethers may be comprised ofnitinol. The one or more tethers may be comprised of a polymericmaterial. The device may include multiple tethers that each extend fromthe body frame portion to the collar that is coupled to the supportwire. Each tether of the multiple tethers may be adapted to evert to aconfiguration wherein each tether of the multiple tethers issubstantially within an area defined by the body frame portion. Thefilter portion may not substantially overlap the body frame portion. Thebody frame portion may define a plurality of open-faced cells arrangedin at least three rows along the longitudinal length of the body frameportion, and the filter portion may overlap the body frame portion by upto one row of the at least three rows and the filter portion may notoverlap the remaining body frame portion. The body frame portion maydefine from three to ten rows of open-faced cells along the longitudinallength of the body frame portion. The filter portion may overlap 20% orless of the longitudinal length of the body frame portion. The one ormore tethers may extend from a proximal end of the body frame portion,and the filter portion may extend from a distal end of the body frameportion.

In another general aspect, a method of treating a thrombus is provided.The method comprises: introducing a catheter to a patient and advancinga distal end of the catheter to a treatment site; advancing a thrombustreatment device through a lumen of the catheter; positioning thethrombus treatment device within the lumen of the catheter at a positionwherein the body frame portion is generally aligned with at least aportion of a thrombus at the treatment site; and proximally withdrawingthe catheter, wherein the body frame portion expands with a radial forcesufficient to embed in the thrombus in response to the proximalwithdrawal of the catheter. The thrombus treatment device comprises: (a)a body frame portion, (b) a tether portion that includes one or moretethers that extend from the body frame portion to a collar that iscoupled to a support wire, and (c) a filter portion that extends fromthe body frame portion, wherein a longitudinal length of the body frameportion is at least two times as long as an outer diameter of the bodyframe portion.

In various implementations, the body frame portion may be adapted toopen a flow channel through or around the thrombus when the body frameportion expands and contacts the thrombus. The filter portion may beadapted to capture thrombus particles displaced by the expansion of thebody frame portion. The method may further comprise pretreating thefilter portion with a thrombogenic material or autologous blood. Thethrombus treatment device may act as an occluder while the thrombogenicmaterial or autologous blood restricts blood flow through the filterportion. The method may further comprise delivering a thrombolytic agentto the thrombus.

In another general aspect, another thrombus treatment device isprovided. The thrombus treatment device comprises: a support tube; abody frame portion that is disposed about an axis defined by the supporttube, the body frame portion including a proximal end and a distal end;a filter portion that extends from the distal end of the body frameportion; and multiple tethers each having a first end and a second end,wherein the first end of each of the multiple tethers extends out aproximal end of the support tube, the tethers extending through a lumenof the support tube and out a distal end of the support tube andengaging the body frame portion near the distal end of the body frameportion and extending to the proximal end of the body frame portion, thesecond end of each of the multiple tethers being attached to the bodyframe portion near the proximal end of the body frame portion.

In various implementations, each tether of the multiple tethers may forma loop around the body frame portion near the proximal end of the bodyframe portion. A proximally directed force applied to the first end ofeach of the multiple tethers may cause the distal end of the body frameportion and the proximal end of the body frame portion to collapseradially toward the axis defined by the support tube. The multipletethers may collectively form a loop around the body frame portion nearthe proximal end of the body frame portion. A proximally directed forceapplied to the first end of each of the multiple tethers may cause thedistal end of the body frame portion and the proximal end of the bodyframe portion to collapse radially toward the longitudinal axis definedby the support tube.

In another general aspect, another method of treating a thrombus isprovided. The method comprises: introducing a catheter to a patient andadvancing a distal end of the catheter to a treatment site; advancing athrombus treatment device through a lumen of the catheter; positioningthe thrombus treatment device within the lumen of the catheter at aposition wherein the body frame portion is generally aligned with atleast a portion of a thrombus at the treatment site; and proximallywithdrawing the catheter, wherein the body frame portion expands with aradial force sufficient to embed in the thrombus in response to theproximal withdrawal of the catheter. The thrombus treatment devicecomprises: (a) a support tube, (b) a body frame portion that is disposedabout an axis defined by the support tube, the body frame portionincluding a proximal end and a distal end, (c) a filter portion thatextends from the distal end of the body frame portion, and (d) multipletethers each having a first end and a second end, wherein the first endof each of the multiple tethers extends out a proximal end of thesupport tube, the tethers extending through a lumen of the support tubeand out a distal end of the support tube and engaging the body frameportion near the distal end of the body frame portion and extending tothe proximal end of the body frame portion, the second end of each ofthe multiple tethers being attached to the body frame portion near theproximal end of the body frame portion.

In various implementations, the body frame portion may be adapted toopen a flow channel through the thrombus when the body frame portionexpands and contacts the thrombus. The filter portion may be adapted tocapture thrombus particles displaced by the expansion of the body frameportion. The method may further comprise pretreating the filter portionwith a thrombogenic material or autologous blood. The thrombus treatmentdevice may act as an occluder while the thrombogenic material orautologous blood restricts blood flow through the filter portion. Themethod may further comprise delivering a thrombolytic agent to thethrombus.

In another general aspect, another thrombus treatment device isprovided. The thrombus treatment device comprises: a support wire; abody frame portion that is disposed about an axis defined by the supportwire, wherein a longitudinal length of the body frame portion is atleast two times as long as an outer diameter of the body frame portion;one or more tethers that each extend from a proximal end of the bodyframe portion to a collar that is coupled to the support wire; and afilter portion that extends from a distal end of the body frame portion.The body frame portion defines a plurality of open-faced cells arrangedin at least three rows along the longitudinal length of the body frameportion, and wherein the filter portion overlaps up to one row of the atleast three rows and does not overlap the remaining rows.

In various implementations, the longitudinal length of the body frameportion may be at least three times as long as the outer diameter of thebody frame portion. The longitudinal length of the body frame portionmay be at least four times as long as the outer diameter of the bodyframe portion. The longitudinal length of the body frame portion may beat least five times as long as the outer diameter of the body frameportion.

In another general aspect, another method of treating a thrombus isprovided. The method comprises: inserting a catheter into a patient andadvancing a distal end of the catheter to a treatment site; advancing athrombus treatment device through a lumen of the catheter; positioningthe thrombus treatment device within the lumen of the catheter at aposition wherein the body frame portion is generally aligned with atleast a portion of a thrombus at the treatment site; and proximallywithdrawing the catheter, wherein the body frame portion expands with aradial force sufficient to embed in the thrombus in response to theproximal withdrawal of the catheter. The thrombus treatment devicecomprises: (a) a body frame portion that has a longitudinal length thatis at least two times as long as an outer diameter of the body frameportion, (b) a tether portion that includes one or more tethers thateach extend from the body frame portion to a collar that is coupled to asupport wire, and (c) a filter portion that extends from the body frameportion, wherein the body frame portion defines a plurality ofopen-faced cells arranged in at least three rows along the longitudinallength of the body frame portion, and wherein the filter portionoverlaps up to one row of the at least three rows and does not overlapthe remaining rows of the at least three rows.

In various implementations, the body frame portion may be adapted toopen a flow channel through the thrombus when the body frame portionexpands and contacts the thrombus. The filter portion may be adapted tocapture thrombus particles displaced by the expansion of the body frameportion. The method may further comprise pretreating the filter portionwith a thrombogenic material or autologous blood. The thrombus treatmentdevice may act as an occluder while the thrombogenic material orautologous blood restricts blood flow through the filter portion. Themethod may further comprise delivering a thrombolytic agent to thethrombus.

In another general aspect, another thrombus treatment device isprovided. The thrombus treatment device comprises: a support tube; abody frame portion that is disposed about an axis defined by the supporttube, the body frame portion including a proximal end and a distal end;a filter portion that extends from the distal end of the body frameportion; one or more proximal tethers each having first and second ends,wherein the first end of each of the one or more proximal tethers iscoupled to the support tube, and wherein the second end of each of theone or more proximal tethers is coupled to the body frame portion; andone or more distal tethers each having first and second ends, whereinthe first end of each of the one or more distal tethers is coupled tothe support tube, and wherein the second end of each of the one or moredistal tethers is coupled to the body frame portion.

In various implementations, the one or more distal tethers may bemovably coupled to the support tube, and wherein the one or moreproximal tethers may be fixedly coupled to the support tube. The one ormore distal tethers may be fixedly coupled to the support tube, and theone or more proximal tethers may be movably coupled to the support tube.A distal end of the support tube may be located distally of a locationwhere the distal tethers are coupled to the support tube. A distal endof the support tube may be located distally of the filter portion. Thedistal tethers may be located substantially within an interior spacedefined by the filter portion. A longitudinal length of the body frameportion may be at least two times as long as an outer diameter of thebody frame portion. A longitudinal length of the body frame portion maybe at least three times as long as an outer diameter of the body frameportion. A longitudinal length of the body frame portion may be at leastfour times as long as an outer diameter of the body frame portion. Alongitudinal length of the filter portion may be less than or equal toone-half of a longitudinal length of the body frame portion. The secondend of each of the one or more proximal tethers may be coupled to theproximal end of the body frame portion, and the second end of each ofthe one or more distal tethers may be coupled to the distal end of thebody frame portion.

In another general aspect, another method for treating a thrombus isprovided. The method comprises: inserting a catheter into a patient andadvancing a distal end of the catheter to a treatment site; advancing athrombus treatment device through a lumen of the catheter; positioningthe thrombus treatment device within the lumen of the catheter at aposition wherein the body frame portion is generally aligned with atleast a portion of a thrombus at the treatment site; and proximallywithdrawing the catheter, wherein the body frame portion expands with aradial force sufficient to embed in the thrombus in response to theproximal withdrawal of the catheter. The thrombus treatment devicecomprises: a support tube; a body frame portion that is disposed aboutan axis defined by the support tube, the body frame portion including aproximal end and a distal end; a filter portion that extends from thedistal end of the body frame portion; one or more proximal tethers eachhaving first and second ends, wherein the first end of each of the oneor more proximal tethers is coupled to the support tube, and wherein thesecond end of each of the one or more proximal tethers is coupled to thebody frame portion; and one or more distal tethers each having first andsecond ends, wherein the first end of each of the one or more distaltethers is coupled to the support tube, and wherein the second end ofeach of the one or more distal tethers is coupled to the body frameportion.

In various implementations, the body frame portion may be adapted toopen a flow channel through the thrombus when the body frame portionexpands and contacts the thrombus. The filter portion may be adapted tocapture thrombus particles displaced by the expansion of the body frameportion.

In another general aspect, another thrombus treatment device isprovided. The thrombus treatment device comprises: a support wire; abody frame portion that is disposed about an axis defined by the supportwire, wherein the body frame portion defines one or more interstices; atether portion that includes one or more tethers, said one or moretethers extending from the body frame portion to a collar that iscoupled to the support wire; and a filter portion that extends from thebody frame portion, wherein, when the collar is positioned substantiallywithin a region interior of the body frame portion or filter portion,articulation of the support wire causes a portion of the one or moretethers to move through a range of motion and does not impartsubstantial motion to the body frame portion.

In various implementations, the articulation of the support may be arotation of said support wire and may cause substantially zero motion ofthe body frame portion. The device may include, with respect to therotation of the support wire, a neutral position associated with azero-degree rotation of the support wire, a first torqued positionassociated with a clockwise rotation of the support wire, and a secondtorqued position associated with a counter-clockwise rotation of thesupport wire. The one or more tethers may comprise an “S” shape when thedevice is in the neutral position. The one or more tethers may comprisea first generally linear shape when the device is in the first torquedposition, and may comprise a second generally linear shape when thedevice is in the second torqued position. The one or more tethers maycomprise a looped configuration when the device is in the neutralposition. The one or more tethers may be adapted to sever, when thesupport wire is articulated, at least a portion of thrombotic materialthat protrudes through the one or more interstices defined by the bodyframe portion. The articulation of the support wire may be a rotation ofthe support wire up to 270 degrees and may cause the portion of the oneor more tethers to sweep through a range of motion and may not impartsubstantial motion to the body frame portion. The articulation of thesupport wire may be a rotation of the support wire up to 180 degrees andmay cause the portion of the one or more tethers to sweep through arange of motion and may not impart substantial motion to the body frameportion. The articulation of the support may be a rotation of saidsupport wire up to 360 degrees and may cause substantially zero motionof the body frame portion.

In another general aspect, another method of treating a thrombus isprovided. The method comprises: inserting a catheter having a proximalend and a distal end into a patient and advancing the distal end of thecatheter to a treatment site; advancing a thrombus treatment device tothe treatment site through a lumen of the catheter; positioning thethrombus treatment device within the lumen of the catheter at a positionwherein the body frame portion is generally aligned with at least aportion of a thrombus at the treatment site, and proximally withdrawingthe catheter; providing a distally directed force to the support wire toadvance the collar to a location substantially within a region interiorof the body frame portion or substantially within a region interior ofthe filter portion; and rotationally actuating the support wire, whereinthe rotational actuation of the support wire causes a swiveling motionof at least a portion of the one or more tethers, the one or moretethers being adapted to macerate the thrombus. The thrombus treatmentdevice comprises: (a) a body frame portion, wherein the body frameportion defines one or more interstices, (b) a tether portion thatincludes one or more tethers, said one or more tethers extending fromthe body frame portion to a collar that is coupled to a support wire,and (c) a filter portion that extends from the body frame portion.

In various implementations, the swiveling motion of the portion of theone or more tethers may sever thrombotic material that protrudes throughone or more interstices defined by the body frame portion. A rotation ofthe support wire may cause the portion of the one or more tethers tosweep through a range of motion without imparting substantial motion tothe body frame portion. The rotation of the support wire through about360 degrees may cause substantially zero motion at the body frameportion. A rotation of the support wire through about 270 degrees maycause the portion of the one or more tethers to sweep through a range ofmotion without imparting substantial motion to the body frame portion.The rotation of the support wire up to at least about 270 degrees maycause substantially zero motion at the body frame portion. A rotation ofthe support wire through about 180 degrees may cause the portion of theone or more tethers to sweep through a range of motion without impartingsubstantial motion to the body frame portion. The rotation of thesupport wire may cause substantially zero motion at the body frameportion. The device may include, with respect to the rotationalactuation, a neutral position associated with a zero-degree rotation ofthe support wire, a first torqued position associated with a clockwiserotation of the support wire, and a second torqued position associatedwith a counter-clockwise rotation of the support wire. The one or moretethers may comprise an “S” shape when the device is in the neutralposition. The one or more tethers may comprise a first generally linearshape when the device is in the first torqued position, and may comprisea second generally linear shape when the device is in the second torquedposition. The one or more tethers may comprise a looped configurationwhen the device is in the neutral position. When the support wire isrotated, the one or more tethers may be adapted to sever thromboticmaterial that protrudes through the one or more interstices defined bythe body frame portion.

In another general aspect, a thrombus treatment system is provided. Thethrombus treatment system comprises: a first support tube; a body frameportion that is disposed about an axis defined by the first supporttube, wherein the body frame portion defines one or more interstices; atether portion that includes one or more tethers, said one or moretethers extending from the body frame portion to a collar that iscoupled to the first support tube; and a stabilization element attachedto a second support tube, wherein, when the collar is positionedsubstantially within a region interior of the body frame portion, arotation of the first support tube up to 360 degrees causes a portion ofthe one or more tethers to sweep through a range of motion and does notimpart substantial motion to the body frame portion.

In various implementations, the one or more tethers may extend from aproximal end of the body frame portion. The one or more tethers mayextend from a distal end of the body frame portion. The one or moretethers may be adapted to sever thrombotic material that enters a regiondefined by the body frame portion in response to a proximally directedforce applied to the second support tube. A rotation of the firstsupport tube up to 270 degrees may cause the portion of the one or moretethers to sweep through a range of motion and may not impartsubstantial motion to the body frame portion. A rotation of the firstsupport tube up to 180 degrees may cause the portion of the one or moretethers to sweep through a range of motion and may not impartsubstantial motion to the body frame portion.

In another general aspect, another method of treating a thrombus isprovided. The method comprises: inserting a catheter into a patient andadvancing a distal end of the catheter to a treatment site; advancing athrombus treatment device to the treatment site through a lumen of thecatheter; advancing the second support tube to a location where thestabilization element is distal of at least a portion of a thrombus atthe treatment site; positioning the body frame portion within the lumenof the catheter at a position proximal of at least a portion of thethrombus; proximally withdrawing the catheter, whereby the body frameportion expands; providing a distally directed force to the firstsupport tube to advance the collar to a location interior of the bodyframe portion; providing a proximally directed force to the secondsupport tube thereby causing the stabilization element to moveproximally; and rotationally actuating the first support tube, whereinthe rotational actuation of the first support tube causes a swivelingmotion of at least a portion of the one or more tethers, and wherein theone or more tethers are adapted to macerate the thrombus. The thrombustreatment device comprises: (a) a first support tube, (b) a body frameportion that is disposed about an axis defined by the first supporttube, (c) a tether portion that includes one or more tethers, said oneor more tethers extending from the body frame portion to a collar thatis coupled to the first support tube, wherein, when the collar ispositioned substantially within a region interior of the body frameportion, a rotation of the first support tube up to 360 degrees causes aportion of the one or more tethers to sweep through a range of motionand does not impart substantial motion to the body frame portion, and(d) a stabilization element attached to a second support tube.

In various implementations, the swiveling motion of the at least aportion of the one or more tethers may macerate thrombotic material thatis displaced proximally by the proximal movement of the stabilizationelement. The device may include, with respect to the rotationalactuation, a neutral position associated with a zero-degree rotation ofthe first support tube, a first torqued position associated with aclockwise rotation of the first support tube, and a second torquedposition associated with a counter-clockwise rotation of the firstsupport tube. The one or more tethers may comprise an “S” shape when thedevice is in the neutral position. The one or more tethers may comprisea first generally linear shape when the device is in the first torquedposition, and may comprise a second generally linear shape when thedevice is in the second torqued position. The one or more tethers maycomprise a looped configuration when the device is in the neutralposition. The method may further comprise, after advancing the secondsupport tube to a location where the stabilization element is distal ofat least a portion of a thrombus at the treatment site, supplying aninflation medium to the stabilization element to cause the stabilizationelement to expand. The inflation medium may be one of a liquid, a gas, agel, a foam, and a solid. The inflation medium may include a contrastagent.

In another general aspect, another thrombus treatment system isprovided. The thrombus treatment system comprises: a first support tube;a body frame portion that is circumferentially disposed about an axisdefined by the first support tube; a first tether portion that includesone or more first tethers, said one or more first tethers extending froma proximal portion of the body frame portion to a first collar that iscoupled to the first support tube; a second tether portion that includesone or more second tethers, said one or more second tethers extendingfrom a distal portion of the body frame portion to a second collar thatis coupled to the first support tube; and a stabilization elementattached to a second support tube, wherein, when the first collar andthe second collar are each positioned within a region interior of thebody frame portion, a rotation of the first support tube causes portionsof the one or more first tethers and the one or more second tethers tosweep through a range of motion and does not impart substantial motionto the body frame portion.

In various implementations, a rotation of the first support tube up to360 degrees may cause portions of the one or more first tethers and theone or more second tethers to sweep through a range of motion and maynot impart substantial motion to the body frame portion. A rotation ofthe first support tube up to 180 degrees may cause portions of the oneor more first tethers and the one or more second tethers to sweepthrough a range of motion and may not impart substantial motion to thebody frame portion.

In another general aspect, another method of treating a thrombus isprovided. The method comprises: inserting a catheter into a patient andadvancing a distal end of the catheter to a treatment site; advancing athrombus treatment device to the treatment site through a lumen of thecatheter; advancing the second support tube to a location where thestabilization element is distal of at least a portion of a thrombus atthe treatment site; positioning the body frame portion within the lumenof the catheter at a position proximal of at least a portion of thethrombus; proximally withdrawing the catheter, whereby the body frameportion expands; positioning the first and second collars within theregion interior of the body frame portion; providing a proximallydirected force to the second support tube thereby causing thestabilization element to move proximally; and rotationally actuating thefirst support tube, wherein the rotational actuation of the firstsupport tube causes a swiveling motion of a portion of the one or morefirst tethers and of a portion of the one or more second tethers, andwherein the one or more first tethers and the one or more second tethersare adapted to macerate the thrombus. The thrombus treatment devicecomprises: (a) a first support tube, (b) a body frame portion that iscircumferentially disposed about an axis defined by the first supporttube, (c) a first tether portion that includes one or more firsttethers, said one or more first tethers extending from a proximalportion of the body frame portion to a first collar that is coupled tothe first support tube, (d) a second tether portion that includes one ormore second tethers, said one or more second tethers extending from adistal portion of the body frame portion to a second collar that iscoupled to the first support tube, wherein, when the first collar andthe second collar are each positioned within a region interior of thebody frame portion, a rotation of the first support tube up to 360degrees causes portions of the one or more first tethers and the one ormore second tethers to sweep through a range of motion and does notimpart substantial motion to the body frame portion, and (e) astabilization element attached to a second support tube.

In various implementations, the swiveling motion of the portion of theat least one first tethers and of the portion of the at least one secondtethers may macerate thrombotic material that is displaced proximally bythe proximal movement of the stabilization element. The device mayinclude, with respect to the rotational actuation, a neutral positionassociated with a zero-degree rotation of the first support tube, afirst torqued position associated with a clockwise rotation of the firstsupport tube, and a second torqued position associated with acounter-clockwise rotation of the first support tube. The one or morefirst tethers may comprise an “S” shape when the device is in theneutral position, and the one or more second tethers may comprise the“S” shape when the device is in the neutral position. The one or morefirst tethers and the one or more second tethers may comprise firstgenerally linear shapes when the device is in the first torquedposition, and may comprise second generally linear shapes when thedevice is in the second torqued position. The one or more first tethersand the one or more second tethers may comprise looped configurationswhen the device is in the neutral position. The method may furthercomprise, after advancing the second support tube to a location wherethe stabilization element is distal of at least a portion of a thrombusat the treatment site, supplying an inflation medium to thestabilization element to cause the stabilization element to expand. Theinflation medium may be one of a liquid, a gas, a gel, a foam, and asolid. The inflation medium may include a contrast agent.

In another general aspect, another thrombus treatment system isprovided. The thrombus treatment system comprises: a first support tubeand a second support tube; a body frame portion; a first tether portionthat includes one or more first tethers, said one or more first tethersextending from a proximal portion of the body frame portion to a firstcollar that is coupled to the first support tube; a second tetherportion that includes one or more second tethers, said one or moresecond tethers extending from a distal portion of the body frame portionto a second collar that is coupled to the second support tube; and astabilization element attached to a third support tube, wherein, whenthe first collar and the second collar are each positioned substantiallywithin a region interior of the body frame portion, a rotationalactuation of the first support tube causes a swiveling motion of aportion of the one or more first tethers, and rotational actuation ofthe second support tube causes a swiveling motion of a portion of theone or more second tethers.

In various implementations, the first tube and the second tube may beadapted to be counter-rotated to cause a first swiveling motion of theone or more first tethers and a second swiveling motion of the one ormore second tethers.

In another general aspect, another method of treating a thrombus isprovided. The method comprises: inserting a catheter into a patient andadvancing a distal end of the catheter to a treatment site; advancing athrombus treatment device to the treatment site through a lumen of thecatheter; advancing the third support tube to a location where thestabilization element is distal of at least a portion of a thrombus atthe treatment site; positioning the body frame portion within the lumenof the catheter at a position proximal of at least a portion of thethrombus; proximally withdrawing the catheter, whereby the body frameportion expands; positioning the first and second collars substantiallywithin the region interior of the body frame portion; providing aproximally directed force to the third support tube thereby causing thestabilization element to move proximally; and rotationally actuating thefirst and second support tubes, wherein the rotational actuation of thefirst support tube causes a swiveling motion of a portion of the one ormore first tethers and the rotational actuation of the second supporttube causes a swiveling motion of a portion of the one or more secondtethers, and wherein the one or more first tethers and the one or moresecond tethers are adapted to macerate the thrombus. The thrombustreatment device comprises: (a) a first support tube, (b) a secondsupport tube, (c) a body frame portion, (d) a first tether portion thatincludes at one or more first tethers, said one or more first tethersextending from a proximal portion of the body frame portion to a firstcollar that is coupled to the first support tube, (e) a second tetherportion that includes one or more second tethers, said one or moresecond tethers extending from a distal portion of the body frame portionto a second collar that is coupled to the second support tube, and (f) astabilization element attached to a third support tube.

In various implementations, the first tube and the second tube may becounter-rotated to cause a first swiveling motion of the one or morefirst tethers and a second swiveling motion of the one or more secondtethers. The swiveling motion of the portion of the one or more firsttethers and of the portion of the one or more second tethers maymacerate thrombotic material that is displaced proximally by theproximal movement of the stabilization element. The device may include,with respect to the rotational actuation, a neutral position associatedwith a zero-degree rotation of the first and second support tubes, afirst torqued position associated with a clockwise rotation of the firstand second support tubes, and a second torqued position associated witha counter-clockwise rotation of the first and second support tubes. Theone or more first tethers may comprise an “S” shape when the device isin the neutral position, and the one or more second tethers may comprisethe “S” shape when the device is in the neutral position. The one ormore first tethers and the one or more second tethers may comprise firstgenerally linear shapes when the device is in the first torquedposition, and may comprise second generally linear shapes when thedevice is in the second torqued position. The one or more first tethersand the one or more second tethers may comprise looped configurationswhen the device is in the neutral position. The method may furthercomprise, after advancing the third support tube to a location where thestabilization element is distal of at least a portion of a thrombus atthe treatment site, supplying an inflation medium to the stabilizationelement to cause the stabilization element to expand. The inflationmedium may be one of a liquid, a gas, a gel, a foam, and a solid. Theinflation medium may include a contrast agent.

In another general aspect, another method of treating a thrombus isprovided. The method comprises: inserting a catheter into a patient andadvancing a distal end of the catheter to a treatment site; advancing athrombus treatment device to the treatment site through a lumen of thecatheter; positioning the thrombus treatment device within the lumen ofthe catheter at a position wherein the body frame portion is generallyaligned with at least a portion of a thrombus at the treatment site, andproximally withdrawing the catheter; providing a distally directed forceto the support wire to advance the collar to a location substantiallywithin an interior of the body frame portion; and providing a proximallydirected force to the support wire to withdraw the collar to a locationexterior of the body frame portion, wherein the advancing andwithdrawing of the collar causes a motion of at least a portion of theone or more tethers, the one or more tethers being adapted to maceratethe thrombus. The thrombus treatment device comprises: (a) a body frameportion, (b) a tether portion that includes one or more tethers, saidone or more tethers extending from the body frame portion to a collarthat is coupled to a support wire, and (c) a filter portion that extendsfrom the body frame portion.

In another general aspect, another thrombus treatment device isprovided. The thrombus treatment device comprises: a support wire; abody frame portion that is disposed about an axis defined by the supportwire, wherein the body frame portion defines one or more interstices; atether portion that includes one or more tethers, said one or moretethers extending from the body frame portion to a collar that iscoupled to the support wire; and a filter portion that extends from thebody frame portion, wherein, when the collar is positioned substantiallywithin a region interior of the body frame portion or filter portion, amanipulation of the support wire causes a portion of the one or moretethers to move through a range of motion and does not impartsubstantial motion to the body frame portion.

In various implementations, the manipulation of the support wire may bea linear movement substantially parallel to the axis. The manipulationof the support wire may be a rotational movement. The rotationalmovement of the support wire may be up to 360 degrees. The rotationalmovement of the support wire may be up to 270 degrees. The rotationalmovement of the support wire may be up to 180 degrees. The device mayinclude, with respect to the rotation of the support wire, a neutralposition associated with a zero-degree rotation of the support wire, afirst torqued position associated with a clockwise rotation of thesupport wire, and a second torqued position associated with acounter-clockwise rotation of the support wire. The one or more tethersmay comprise an “S” shape when the device is in the neutral position.The one or more tethers may comprise a first generally linear shape whenthe device is in the first torqued position, and may comprise a secondgenerally linear shape when the device is in the second torquedposition. The one or more tethers may comprise a looped configurationwhen the device is in the neutral position. The one or more tethers maybe adapted to sever, when the support wire is rotated, at least aportion of thrombotic material that protrudes through the one or moreinterstices defined by the body frame portion.

Particular embodiments of the subject matter described in thisspecification can be implemented so as to realize one or more of thefollowing advantages. Treatment to reduce thrombi and restore blood flowcan be administered while preventing the release of thromboemboli intothe bloodstream. Thrombotic material can be macerated and removed whileprotecting blood vessel walls from potential trauma. A single device canprovide a treatment platform for performing multiple procedures, such asthrombolysis, aspiration, maceration, and thrombectomy, while providingthromboembolic protection.

The details of one or more embodiments of the subject matter of thisspecification are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages of thesubject matter will become apparent from the description, the drawings,and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example thrombectomy device.

FIGS. 2A-2I are a series of illustrations depicting an example manner ofuse of an example thrombectomy device.

FIG. 3 is a photograph of an embodiment of an example thrombectomydevice.

FIG. 4 illustrates an example embodiment of a method for performing athrombectomy procedure.

FIGS. 5A-5F illustrate an example thrombectomy system and an examplemanner of use of an example thrombectomy system.

FIGS. 6A-6B illustrate an example thrombectomy system and an examplemanner of use of an example thrombectomy system.

FIG. 7 illustrates an example thrombectomy device.

FIG. 8 illustrates an example embodiment of a method for performing athrombolysis procedure.

FIG. 9 illustrates another example thrombectomy device.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

FIG. 1 illustrates an example embodiment of a thrombectomy device 10.This device can be delivered percutaneously and through a patient'svasculature to the site of a thrombus, such as a neurovascular,cardiovascular, or peripheral vein thrombus site. The thrombectomydevice 10 may be used in both antegrade and retrograde applications.

The example thrombectomy device 10 generally includes a support wire 15and a distal device body 12 including three (3) primary components: (i)a tether assembly 20, (ii) a body frame 30, and (iii) a filter bag 40. Acentral collar 18 can couple the tether assembly 20 to the support wire15. The distal device body is collapsible so it can be contained withina catheter lumen for delivery through the patient's vasculature to thelocation of a thrombus (refer, e.g., to FIGS. 2D and 2E). At thethrombus site, the thrombectomy device 10 can be deployed outwardly fromthe distal tip of the delivery catheter, at which time the thrombectomydevice 10 can expand to the unconstrained configuration shown in FIG. 1.

The support wire 15 can include a solid or hollow support wire, or caninclude any other tubular article with at least one continuous lumenrunning therethrough. A suitable support wire 15 for use with thethrombectomy device 10 may include, but is not limited to, a guide wireor a tube (e.g., a support tube). In general, the support wire 15 canenable the thrombectomy device 10 to be delivered through tortuousvascular anatomies and positioned in distal vascular areas. In someembodiments, support wire 15 extends through the distal end of thefilter bag 40 to become the most distal component of the thrombectomydevice 10. In some embodiments, support wire 15 extends into the distaldevice body 12 but not through the distal end of the filter bag 40. Insome embodiments, a support wire 15 that extends distally from at leastthe body frame 30 can also include one or more balloon devices disposednear the distal end.

In some embodiments, the support wire 15 is a flexible driveshaft asdescribed in the patent application titled “Flexible Driveshafts withBi-Directionally Balanced Torsional Stiffness Properties,” havinginventor Clifford P. Warner, filed on the same date as this application,and which is herein incorporated by reference in its entirety for allpurposes.

The tether assembly 20 of the thrombectomy device 10 includes one ormore tethers 22. The tethers 22 are generally elongate elements that canbe coupled on one end with the support wire 15 (using one or morecollars, such as central collar 18), and the tethers 22 can be coupledwith the body frame 30 at the tether's 22 opposite end. In someembodiments, the tethers 22 extend from the support wire 15 to theproximal end of the body frame 30 (as shown). In some embodiments, thetethers 22 extend from the support wire 15 to the distal end of the bodyframe 30 (not shown). In some embodiments, the tethers 22 extend fromthe support wire 15 to locations on the body frame 30 between theproximal and distal ends of the body frame 30 (not shown). While in someembodiments just one tether 22 is included, some embodiments includetwo, three, four, or more tethers 22.

The length of the tethers 22 can be determined in accordance with theoperational characteristics desired. For example, in some applications ashort deployment length is desired, leading to a selection of short orlooped support strut tethers 20. In some applications the ability toevert the tethers 22 within the body frame 30 or filter bag 40 leads toa selection of using longer tethers 22, which may also be looped in someexamples. For example, in some embodiments the tethers 22 can be atleast as long as the combined length of the body frame 30 and filter bag40. In some implementations, the tethers can be at least twice as longas a diameter defined by the frame body 30 in an unconstrainedconfiguration.

In some embodiments, the tethers 22 of a thrombectomy device 10 are ofsubstantially equal length. In some embodiments, one or more tethers 22are unequal in length in comparison to one or more other tethers 22. Insome embodiments, the tethers 22 of a thrombectomy device 10 are ofsubstantially equal cross-sectional size and/or shape. In someembodiments, one or more tethers 22 are unequal in cross-sectional sizeand/or shape in comparison to one or more other tethers 22.

The tethers 22 can be comprised of generally flexible biocompatiblematerials. For example, in some embodiments the tethers 22 can be madefrom nitinol that exhibits superelasticity. In some embodiments, thetethers 22 may be made from the same material as the body frame 30. Inother embodiments, the tethers 22 can be a polymeric material that ishighly flexible. In some embodiments the tethers 22 can be made from acombination of biocompatible materials that, when combined, exhibitappropriate flexibility. In some examples, the tethers 22 can include anitinol component and a polymeric material component. In someembodiments, the tethers 22 have mechanical properties that make themsuitable for performing maceration of thrombus material as describedfurther below (refer to FIGS. 2G, 5F, and 6B). For example, in some suchembodiments the tethers 22 have a stiffness and sharpness that canfacilitate their effectiveness as maceration implements.

The tethers 22 can be configured as “looped support struts” as describedin U.S. Pat. No. 8,231,650 to Cully et al., which is hereby incorporatedby reference in its entirety for all purposes. When the tethers 22 areconfigured in the looped support strut embodiment, the tethers 22 may beessentially s-shaped in some embodiments, and the central collar 18 canbe everted within the interior of the body frame 30 or the filter bag40, as will be described below (e.g., in regard to FIG. 2G).

The tethers 22 can serve multiple purposes. For example, one purpose ofthe tethers 22 can be to couple the distal device body 12 of thethrombectomy device 10 to the support wire 15. Another purpose of thetethers 22 can be to enable flexible compliance between the body frame30 and the contours of irregularly shaped thrombi or vessel walls.Another purpose can be to provide supplemental radial force between thebody frame 30 and a thrombus so as to open (also known asrecanalization) or maintain a blood-flow path. Another purpose (asdescribed further below) can be to sever, shave, or break up thrombi byeverting and causing a pivoting motion of the tethers 22 as a part of athrombectomy procedure. In some implementations, the tethers 22 need notbe everted to sever, shave, or break up thrombi and participate in thethrombectomy procedure. In some implementations, the tethers 22 may becoated with an abrasive material, which may aid the tethers in severing,shaving, or breaking up thrombi when pivotal motion is applied to thetethers 22. In some implementations, a portion of the tethers may besharpened, which may aid the tethers in severing, shaving, or breakingup thrombi when pivotal motion is applied to the tethers 22.

The body frame 30 can be metallic, for example, constructed of nitinol,stainless steel, titanium, or a combination of materials. The body frame30 materials can, in some embodiments, be laser cut to the desiredconfiguration. In some embodiments body frame 30 can have a polymericcovering or powder coating over a metallic frame. In general, the bodyframe 30 can be collapsible to fit within the lumen of a deliverycatheter. The body frame 30 can radially self-expand to an unconstrainedconfiguration when deployed from the catheter. The unconstrained bodyframe 30 can be circular in cross-section, or another cross-sectionalshape such as a partial circle or an oval. In some embodiments, the bodyframe 30 can have a tapered profile. In some implementations, the bodyframe 30 will radially self-expand to conform to the cross-sectionalshape of a vessel in which the body frame 30 is deployed.

The length of the body frame 30 can be determined in accordance with theoperational characteristics desired, such as the length, thickness,shape, and the location of the thrombus to be treated. The body frame 30can be made longer by, for example, by adding more rows of struts orsupport members to the body frame 30, or by increasing the length of oneor more existing rows of struts. The terms “row” or “rows” as used inrelation to the body frames of the devices provided herein refers to aperipheral portion of the body frame (e.g., a complete helical turnaround the circumference, circumferential ring, or cylindrical portion)corresponding to a segment of the framework of the device. The bodyframe 30 can be constructed using any suitable configuration of strutsor support members. For example, in some embodiments the body frame 30is a helical structure comprising helical rows of strut members. In someembodiments, the body frame 30 is an assembly of one or morecircumferential rings (or rows) of strut members.

In some embodiments, the ratio of the length of the body frame 30 to theouter diameter of the body frame 30 when the thrombectomy device 10 isin an unconstrained and expanded state is about 1:1, about 2:1, about3:1, about 4:1, about 5:1, about 6:1, about 7:1, about 8:1, or more thanabout 8:1. As described further below, the body frame 30 can bepositioned in alignment with a target thrombus and can be deployed toexpand within and/or around the thrombus to open or enlarge a blood-flowpath through and/or around the thrombus. In other words, to recanalizethe blood-flow path.

The diameter of the body frame 30 can be generally correlated to thesize of the vessel in which the thrombectomy device 10 will be deployed.For example, in some applications, some embodiments have a body frame 30diameter of about 2 mm to about 6 mm, or about 4 mm to about 8 mm, orlarger. In other applications, some embodiments have a body frame 30diameter of about 8 mm to about 12 mm, about 10 mm to about 16 mm, about14 mm to about 22 mm, about 20 mm to about 28 mm, or larger. Asillustrated by these two examples, a continuum of body frame 30 diametersizes are envisioned within the scope of this document. That is, athrombectomy device 10 can be appropriately sized to treat any and allbodily vessels. In some embodiments, devices with a generally smallersize are used in neurovascular applications. In some embodiments,devices with a generally larger size are used in peripheral veinapplications.

In some embodiments, the body frame 30 can have a generally open latticeconstruction. That is, in the expanded configuration, the wall of thebody frame 30 can have a substantial amount of area that is open (areasthat are not blocked by frame material). In some embodiments, the wallof the body frame 30 can have a higher density of frame material (suchas strut elements 32). In comparison, open lattice construction mayallow for more penetration of thrombus material while providing lessradial displacement of thrombus material, whereas a higher density offrame material may allow for more radial displacement (compaction) ofthrombus material and less penetration of thrombus material. Thus, abody frame 30 with a generally open lattice construction can, in someembodiments, be well-suited to allowing penetration of thrombus materialwithin the interior of the body frame 30 where the thrombus material canbe detached and removed (reference FIGS. 2G, 2H, and 6B); and a bodyframe 30 with higher density of frame material can, in some embodiments,be well-suited to compressing thrombus material against the wall of avessel, thereby facilitating recanalization of the vessel. In someembodiments, the body frame 30 can be designed to provide an appropriateblend of both thrombus penetration and radial displacement of thrombus,or predominantly one or the other, as desired.

Strut elements 32, in some embodiments, can be connected by bridgeelements. The strut elements 32 can include a variety of configurations,such as diamond-shaped, “v”-shaped, and braided mesh. In someembodiments where the strut elements 32 form generally diamond-shapedcells (see, e.g., FIG. 3), the device may be lengthened by addinganother row of diamond cells. To enhance the compliance of the bodyframe 30 with irregularly-shaped vessel configurations, in someembodiments, highly-flexible interstitial linkage members can beincluded to interconnect adjacent rows of strut elements 32. The linkagemembers can be, in some embodiments, comprised of expandedpolytetrafluoroethylene (ePTFE) and/or other flexible polymericmaterials.

In general, embodiments of the self-expanding body frame 30 can providea substantial radial force, while exhibiting a minimal lateralresistance to being collapsed to a low profile for placement in adelivery catheter. The radial force can be used to open or maintain ablood-flow path through or around a thrombus. The minimal lateralresistance to being collapsed is useful for positioning andrepositioning the body frame 30 within the small diameter of a deliverycatheter. Interstices in the body frame 30 provide open spaces betweenthe strut elements 32 that can allow for portions of a thrombus toprotrude within the interior of the body frame 30. Portions of thrombusin the interior of the body frame 30 can be removed by, for example,aspiration or maceration (as described below).

In some implementations, the body frame 30 may remain in a patient'svasculature only while the patient is undergoing a thrombectomy, and maygenerally remain coupled to support wire 15 throughout the treatment.The thrombectomy device 10 may be used to collect thrombotic materialfrom the vasculature, so that the material may be safely removed fromthe vasculature, and may minimize a risk that the material may traveldownstream of the device through the vasculature.

The filter bag 40 of the example thrombectomy device 10 can be attachedto and extend from an end of the body frame 30. In some embodiments thefilter bag 40 is attached to a distal end of the body frame 30. In someembodiments, the filter bag 40 can overlap a portion of the body frame30, such as up to about one, or more than one, distal rows of strutelements 32 (see, e.g., FIG. 3), such that the body frame 30 provides asupport structure underlying at least a portion of the filter bag 40. Insome embodiments, the filter bag 40 does not overlap the body frame 30and the filter bag 40 is unsupported other than by its attachment to thedistal end of the body frame 30. U.S. Publication 2005/0177186 to Cullyet al., which is hereby incorporated by reference in its entirety forall purposes, describes various filter bag embodiments and methods ofmaking and using filter bags that can be applicable to the embodimentsprovided herein.

In some embodiments, the longitudinal length of the filter bag 40 isapproximately proportionate to the length of the body frame 30. Forexample, in some embodiments the length of the filter bag 40 is lessthan or equal to about one-half of the length of the body frame 30. Insome embodiments, the length of the filter bag 40 is about one-half ofthe length of the body frame 30 to about equal to the length of the bodyframe 30. In some embodiments, the length of the filter bag 40 isgreater than the length of the body frame 30.

In general, filter bag 40 can capture and contain thromboemboli, plaque,and other particulate, while enabling pass-through flow of blood. Thefilter bag 40 can be made from a variety of filter media materials. Forexample, the filter media can be a laser perforated layer of thinpolytetrafluoroethylene (PTFE). In some embodiments, the range of poresizes of the filter media can be from 20-30 μm, 30-50 μm, 50-70 μm,70-80 μm, or 80-100 μm. In some embodiments, the pore sizes of thefilter media can differ depending on the region of the filter bag. Insome embodiments, the filter media can be treated to become hydrophilic,such as by dipping the media in a heparin solution or polyvinyl alcoholsolution. Treating the filter media with heparin solution can provide anadditional benefit, in certain implementations, of inhibiting thrombusformation at holes in the media, which may enhance blood flow throughthe holes in the media.

FIGS. 2A-2I illustrate example devices, systems, and processes fortreatment of thrombi. In general, the embodiments and concepts describedcan be applied in virtually any vascular region containing thrombi, forexample, neurovascular, cardiovascular, and peripheral vessels, and inboth arterial and venous vasculature systems. The embodiments andconcepts described generally pertain to: (1) opening a blood-flow paththrough a vessel obstructed by a thrombus and (2) capturing and removingan amount of thrombotic material.

FIG. 2A illustrates an example vasculature portion 210 including athrombus 230 at a thrombus site 235. The thrombus 230 can be, forexample, attached to or lodged against a vessel wall 225, or lodgedwithin a vessel 220. The thrombus 230 can partially or completely blockthe blood flow 226 through vessel 220. While the example of FIG. 2Adepicts a thrombus 230 that partially blocks blood flow 226 throughvessel 220, the devices and techniques described herein may also be usedfor clots or thrombi that completely block blood flow through a vessel.

Typically, access to the thrombus 230 can be initially achieved by aflexible guidewire 250. In some cases, other devices such as one or moreguide catheters (not shown) may also be used to navigate through thepatient's vasculature to a location near a target thrombus. In somecases, access to the thrombus can be achieved by the combination of oneor more guide catheters and guidewires. For example, a combination ofsuccessively smaller guide catheters can be arranged in a telescope-likefashion. In some implementations, guidewire 250 can be inserted invessel 220 so that the distal tip of guidewire 250 extends past thethrombus site 235.

FIG. 2B illustrates an example catheter 240 installed over the guidewire250. The previously inserted flexible guidewire 250 can be used to pilotthe insertion of the catheter 240 in an over-the-wire manner. In someapplications, the catheter 240 can be a micro-catheter having an innerdiameter of, for example, 0.021 inches or 0.027 inches. Proportionatelylarger catheters can be used in larger vessels as determined by aclinician operator. In some implementations, the catheter 240 can beadvanced to a position so that its distal tip extends past the thrombussite 235.

FIG. 2C illustrates the removal of the guidewire 250 from the catheter240. In this embodiment, the guidewire 250 aided the navigation of thecatheter 240 to a desired position. With the catheter 240 in the desiredposition, the guidewire 250 can be removed to make room within the lumenof catheter 240 for insertion of other devices to treat the thrombus230, and other vessel obstructions or conditions, according to someimplementations. In some embodiments, the guidewire 250 is left inplace, whereby the guidewire 250 can be used to facilitate additionaldeployment operations.

FIG. 2D illustrates the insertion of an example thrombectomy device 10through the lumen of catheter 240. In this delivery configuration, thethrombectomy device 10 is in a collapsed state to fit within the lumenof catheter 240. In some implementations, the thrombectomy device 10 canbe advanced so that at least its distal tip extends past the thrombussite 235. In some implementations, it may be desirable to position thethrombectomy device 10 such that a majority or substantially the entirefilter bag 40 is located beyond (e.g., distal of) the thrombus 230.

While FIGS. 2A-2I depict an implementation in which the target thrombus230 is generally concentric with the vessel 225, in some implementationsa thrombus is eccentrically positioned within a vessel. That is, thelocation of the thrombus may be biased to a particular side of thevessel. In such implementations, the catheter 240 can be inserted around(rather than through) the thrombus. However, the principles of operationof the thrombectomy device 10 in the context of an eccentricallypositioned thrombus are generally the same as described herein inrelation to the concentric thrombus of FIGS. 2A-2I.

FIG. 2E illustrates an example thrombectomy device 10 in an expanded(e.g., deployed) configuration within a thrombus 230. In someimplementations, this arrangement can be achieved by retracting thecatheter 240 from the position shown in FIG. 2D, while maintaining orrestraining the thrombectomy device 10 in its prior (e.g., as shown inFIG. 2D) axial position with respect to the thrombus 230. That is, thecatheter 240 can be drawn backward (proximally) while holding thethrombectomy device 10 in place to cause the emergence of thethrombectomy device 10 from the lumen of the catheter 240.

As described previously, the body frame 30 of the thrombectomy device 10can, in some embodiments, be self-expanding. That is, the body frame 30can have a shape-memory characteristic that urges the frame to assume anexpanded configuration (refer to FIG. 1) when it is unconstrained (e.g.,unconstrained after emerging from a delivery catheter). In someembodiments, the body frame 30 may assume a partially expandedconfiguration when it is partially constrained (as by thrombus 230), asshown in FIG. 2E. In some embodiments, such as those with an openlattice construction, the body frame 30 can penetrate completely, ormacerate, through at least a portion of thrombus 230 to come intocontact with the inner vessel wall 225. In any case, the thrombectomydevice 10 will expand such that the filter bag 40 will substantiallymake contact with the inner vessel wall 225 before the entirety of thebody frame 30 is deployed. In that manner, one or more dislodgedthrombotic fragments separated from the thrombus 230 by deployment ofthe body frame 30 can be captured by the filter bag 40.

The expansion of the thrombectomy device 10 as it exits the catheter 240may open or enlarge a blood-flow 226 path through or around the thrombus230, according to some implementations. In some embodiments, such asthose with a relatively higher density of frame material, the body frame30 can exert substantial radial force against the thrombus 230 tocompact the thrombus 230 against inner vessel wall 225. That is, theradial force associated with the expansion of the body frame 30 can beexerted on the surrounding or adjacent thrombus 230 so as to displace orcompact at least a portion of the thrombotic material, thereby openingor enlarging a blood-flow 226 path (also known as recanalization). Inthat case, the blood-flow 226 path can include a path through the innerregion of the body frame 30. Hence, a blood-flow 226 path can be createdor enlarged as a result of the displacement of the thrombotic materialby the action of the expanding body frame 30. Because blood includesnatural lytic agents, the creation or expansion of the blood-flow 226path through the thrombus 230 may, in some embodiments, encourageadditional reduction of the thrombus 230 as the blood's natural lyticagents work to attack the thrombus 230.

The proximal portion of the filter bag 40 can be in contact with theinner vessel wall 225. Thus, if thrombotic fragments are dislodged fromthe thrombus 230 as a result of the displacement or maceration of thethrombotic material by the body frame 30, the thromboemboli can becaptured by the filter bag 40. For example, liberated thromboemboli maybe carried by blood via the blood-flow path distally through the bodyframe 30 and into a space defined by the filter bag 40. The blood maythen pass through the filter bag, for example through small pores in thefilter bag, while the thromboemboli may be captured or trapped withinthe filter bag 40 because the thromboemboli may be too large to passthrough the pores in the filter bag. In this manner, dislodgedthrombotic fragments can be prevented from becoming fugitivethromboemboli within the bloodstream.

In the case of a neurological vascular thrombus occlusion, restoringperfusion as described above is an initial treatment pursuant to savinga patient's life. Restoring downstream perfusion, even if only partialperfusion, restores blood flow to downstream neurological tissues.Restoring blood flow may also minimize and/or eliminate the pressure ofblood pushing on the thrombus 230 and the vacuum or negative pressurelocated just distally of the thrombus 230. The reduction or eliminationof that pressure differential on the sides of the thrombus 230 canenhance the effectiveness of the thrombectomy device 10.

In some embodiments, the construction of the body frame 30 can permitsome portions of the thrombus 230 to penetrate between the strutelements 32 to within the inner region of the body frame 30, as can beenseen in FIG. 2E. The same can occur between the tethers 22, in someimplementations. As described further below, the penetration ofthrombotic material to within the body frame 30 and tethers 22 can allowfor additional treatment procedures to reduce the size of the thrombus230.

FIG. 2F illustrates some examples of the thrombectomy techniques thatcan be performed using the thrombectomy device 10. In particular, as aresult of opening or enlarging a blood-flow path as described above, anincreased amount of blood can then flow over the surface of the thrombus230, thereby encouraging thrombolysis of thrombus 230. That is, causingadditional blood to flow over the surface of the thrombus 230 canenhance the effects from blood's natural tendency to dissolve thethrombus. The blood's lytic action may partially erode surface 232 ofthrombus 230 by dissolving some of the thrombus 230, or by dislodgingsome thrombotic particles. Dislodged thrombotic particles can becaptured in filter bag 40 to prevent them from becoming thromboemboli inthe bloodstream. One or more portions of thrombus 230 protruding throughthe tethers 22 and/or body frame 30 can be exposed to the increasedblood-flow and potentially dissolved by the blood's lytic tendencies. Insome examples, even portions of the thrombus 230 that do not protrudethrough a portion of the body frame 30 or the tethers 22 may be reducedin size or eliminated because of increased exposure to blood flow andthe associated increased lytic action such increased exposure mayprovide to break down or dissolve the thrombus 230.

As can be seen with reference to FIG. 2F, device 10 is a single devicedelivered over a single catheter. Filter bag 40 is integral with bodyframe 30, being attached to a distal end of body frame 30 or overlappedwith a portion of body frame 30 in some implementations. In someembodiments, no portion of filter bag 40 is directly attached to supportwire 15. Moreover, device 10 includes only one attachment point tosupport wire 15 in some implementations, namely, via collar 18, whichfixedly couples tethers 22 to the support wire 15.

FIG. 2G illustrates additional examples of thrombectomy techniques thatcan be performed by some embodiments of the thrombectomy device 10. Sometechniques involve articulation and/or manipulation of the support wire15 in various manners. Some techniques involve pushing the support wire15 forward to advance the support wire 15 in the direction of arrow 17,which may advance collar 18 to a location interior of the body frame 30(e.g., to a location within an interior region defined by body frame30), or to a location within the filter bag 40 (e.g., to a locationwithin an interior region defined by filter bag 40). In someembodiments, the advancing of the support wire 15 can be accomplishedusing, for example, a lead screw or lever device at an actuator coupledto the proximal end of the support wire 15. In other cases, the supportwire 15 can be manually advanced by a clinician operator. In general,the body frame 30 and filter bag 40 may not substantially movelongitudinally in relation to the vessel wall 225 in response to thesupport wire 15 and collar 18 being advanced. The body frame 30 andfilter bag 40 remain substantially stationary longitudinally because ofthe interference fit of the body frame 30 with the thrombus, and becausethe tethers 22 can become everted as the support wire 15 is advanced.

In some embodiments, the one or more tethers 22 (some embodimentsinclude a single tether, and some embodiments include more than onetether) can have shape-memory characteristics so that the one or moretethers 22 will automatically position themselves during deployment tothe configuration approximately as shown. That is, in some embodimentsthe device will deploy, based on a shape memory property of the one ormore tethers 22, so that the one or more tethers 22 are everted andsubstantially reside within a space defined by the body frame 30.

Because of the lengths of the individual tethers 22, which may in someembodiments have lengths at least about two times a diameter of anopening defined by the body frame 30 in an unconstrained state,advancing the collar 18 to a location interior of the body frame 30 mayimpart only a minimal force or substantially no force to the body frame30 of the device, and thus the body frame 30 may generally maintain itsposition with respect to the thrombus 230 as the collar 18 is advanced.While the body frame 30 can, in some embodiments, remain stationary withrespect to the thrombus 230, the central collar 18 and tethers 22 areadvanced forward to positions within the interior of the body frame 30,and in some embodiments within the filter bag 40. In particular, thetethers 22 in this manner have been everted, for example, as disclosedin U.S. Publication 2005/0101989 describing looped support strutelements, the contents of which are incorporated herein in its entiretyfor all purposes, including for its discussion of making frame and strutstructures.

Portions of the everted tethers 22 may be in close proximity to the bodyframe 30 of the thrombus treatment device. That is, as the evertedtethers loop from a proximal end of the body frame 30 to the collar 18,a substantial portion of the tether may be adapted to reside adjacent orsubstantially adjacent an inward-facing portion of the body frame 30. Inthis configuration, the everted tethers 22 may make contact withportions of the thrombus 230 that have penetrated through theinterstices of the body frame 30 to within the inner region of the bodyframe 30. In some embodiments, the effectiveness of this thrombectomytreatment can be enhanced by having long and flexible tethers 22 thatare configured to make contact with all or a portion of the thrombus 230in the inner region of the body frame 30. In some embodiments, theeffectiveness of thrombectomy treatment can be enhanced by introducingan inflatable balloon device within the inner region of the body frame30 that can be inflated to urge the tethers 22 into contact with all ora major portion of the thrombus 230 in the inner region of the bodyframe 30. In some embodiments, such a balloon device can be located onsupport wire 15, or in some embodiments it can be a separatecomplimentary device located on another support wire/tube.

In some embodiments, the balloon device is as described in theprovisional Patent Application No. 61/678,898 titled “Space-FillingDevice,” having inventors Edward H. Cully and Michael J. Vonesh, filedon Aug. 2, 2012, and which is herein incorporated by reference in itsentirety for all purposes.

With the everted tethers 22 in contact with portions of thrombus 230 inthe interior of the body frame 30, the removal of some additionalthrombotic material may be accomplished in the following manner. Forexample, the support wire 15 may be articulated and/or manipulated. Insome cases, the support wire 15 can be rotated or twisted as indicatedby arrows 16, alternatively clockwise and then counterclockwise (or viceversa), and, in some embodiments, repeated one or more times such that arotational force is imparted from the support wire 15, through thecollar 18, to the tethers 22. The tethers 22 or portions of the tethers22 may thus rotate and act as cutting blades to sever, shave, or breakapart portions of thrombus 230 that protrude through openings of thebody frame 30. That is, the clinician operator can, manually or with theassistance of a mechanism, actuate a twisting motion at the proximal endof support wire 15 which translates to a twisting of the distal end ofthe support wire 15 and causes a swiveling or pivoting motion of aportion of the tethers 22, the force being applied to the tethers 22only at one end of the tethers (the end coupled to the collar 18). Inresponse, the tethers 22 will be swiveled to cut through some portionsof thrombus 230 that are protruding through body frame 30.

For example, in some implementations the support wire 15 can be twistedapproximately 180° or 270° clockwise from the neutral starting position,returned to the neutral starting position, and then 180° or 270°counter-clockwise from the neutral starting position. In someimplementations, the rotation of the support wire 15 can be limited byhaving, for example, hard-stops to prevent rotation beyond that whichthe tethers 22 are capable of handling without imparting forces on thebody frame 30 which could otherwise cause movement of the body frame 30.The hard stops may be incorporated, for example, by a hub device at aproximal end that includes a handle or knob that an operator ormotorized element may move to rotate the support wire 15. In otherexamples, any appropriate amount of rotation can be applied (e.g., about30°, 45°, 60°, 90°, 120°, 135°, 150°, 180°, 210°, 225°, 240°, 270°,300°, 315°, 330°, 360°, or rotations in excess of 360°).

This rotary motion can be repeated as needed in attempt to ensure thatall the thrombotic material that can be severed has been severed.However, in some implementations, a single twisting motion (or notwisting motion) may be all that is required to adequately sever thethrombotic material as needed. In some embodiments, depending on thelength and flexibility of the tethers 22, the twisting actuation of thesupport wire 15 can be 360° or more. Thrombotic material that is severedcan be captured by the filter bag 40 to prevent the severed materialfrom becoming thromboemboli in the bloodstream. Alternatively oradditionally, the severed thrombotic material may be collected andremoved from the bloodstream using aspiration. The aspiration may beperformed using the guide catheter that was used to deploy thethrombectomy device, or an additional aspiration catheter may be used.

Because of the lengths of the individual tethers 22, which may in someembodiments have lengths at least about two times a diameter of anopening defined by the body frame 30 in an unconstrained state, therotational force applied to the support wire 15, and through the collar18 to the tethers 22, may substantially dissipate over the length of thetethers so that only a reduced force, in some cases a minimal orsubstantially zero force, is transmitted to the body frame 30 of thethrombectomy device 10. In this manner, damage to the vessel wall may beminimized because the body frame may not substantially rotate orsubstantially move longitudinally as the support wire is rotated.

By using longer tethers 22, the everted tethers 22 can be positionedcloser to the interior wall of the body frame 30 in someimplementations. In some examples, the position of the central collar 18may be within the interior of the filter bag 40. In some embodiments,substantially the entire inner wall of the body frame 30 can becontacted or nearly contacted by the everted tethers 22. In someembodiments, the tethers 22 can be manufactured with sharpened edges orwith specialized cutting designs to improve their cutting abilities. Thevessel wall 225 can be protected from potential trauma related to theremoval of thrombotic material by the cutting action of the evertedtethers 22 because the body frame 30 can act as a barrier between thevessel wall 225 and the tethers 22 to protect the vessel wall 225. Usingthis thrombectomy technique, at least some of the portions of thrombus230 that are protruding within body frame 230 may be severed from thethrombus 230 and collected in the filter bag 40.

In some embodiments, rather than twisting the support wire 15 to causethe tethers 22 to sever portions of thrombus 230, the support wire 15can be articulated and/or manipulated by advancing the support wire 15proximally (in the direction of arrow 17) and withdrawing the supportwire 15 distally to cause the tethers 22 to move and potentially severportions of thrombus 230. The advancing and withdrawing movements(without substantially rotational movement) can be repeated as desiredto cause the severance of some portions of thrombus 230.

FIG. 2H illustrates additional examples of thrombectomy techniques thatmay be performed by embodiments of the thrombectomy device 10. With thetethers 22 in the everted configuration, the catheter 240 (or anothercatheter) can be moved forward such that the distal tip of the catheter240 is near to the tethers 22 or to the collar 18. Radiopaque markersthat can be used, for example at or near the distal tip of the catheter240, can enhance visualization of the position of the catheter 240. Withthe distal tip of catheter 240 near or inside of the interior of thebody frame 30, additional treatment techniques can be possible. Forexample, the catheter 240 can be used for aspiration of the thrombus 230or fragments of the thrombus 230. In general, aspiration can includeapplying a suction source to the lumen of catheter 240 so that portionsof thrombus 230 can be removed from the thrombus site 235 by suctioningthem into the lumen of catheter 240. In addition, a suction forceapplied via catheter 240 (or another catheter), may be used to aspiratethrombotic material that has collected within the filter bag 40 prior toremoval of the thrombectomy device 10. Removal of the embolic load priorto removal of the thrombectomy device 10 can minimize the risk ofreleasing those emboli during the thrombectomy device 10 retrievalprocedure.

The position of the tip of catheter 240 also lends itself to being usedas a conduit to deliver one or more thrombolytic pharmacological agentsdirectly to or near to the thrombus 230.

Thrombotic material that is dislodged by these techniques can becaptured by the filter bag 40 to prevent the dislodged material frombecoming thromboemboli in the bloodstream.

FIG. 2I illustrates an example of the removing the thrombectomy device10 from the thrombus site 235. As the thrombectomy device 10 is removedfrom the vessel 220, some remaining thrombotic material from thrombus230 may be pulled along with the body frame 30 or tethers 22. As aresult of the thrombectomy techniques performed by the thrombectomydevice 10, in some cases, only the eroded surface 232 of the previousthrombus 230 may remain at the thrombus site 235, or, in some cases,substantially no thrombotic material may remain. The removed thromboticmaterial can have been captured by the filter bag 40 and removed fromthe patient's vasculature by suction as described above or by beingretained in the filter bag 40, in some implementations.

FIG. 3 depicts an example thrombectomy device 300. This particularexample thrombectomy device is sized approximately for a small vessel,such as a vessel to be treated as part of a neurovascular thrombectomyprocedure. As can be seen, the length of the body frame 330 is about 15mm and the outer diameter of the body frame 330 is about 5 mm. Thus, theratio of the length of the body frame 330 to the diameter of the bodyframe 330 is about 3:1, with the thrombectomy device 300 in an expandedand unconstrained state. In some embodiments, the ratio of the outerdiameter to the length of an expanded and unconstrained body frame isabout 4:1, about 5:1, about 6:1, about 7:1, or about 8:1, or more.

The thrombectomy device 300 exhibits many of the components describedabove. For example, the tether assembly 320 includes tethers 322 thatare coupled on one end with a central collar 318 and with a body frame330 on the opposite end. The body frame 330 includes rows of strutelements 332. In this embodiment, there are three (3) rows of strutelements 332. The open-faced cells of the strut elements 332 areconfigured generally in diamond shapes. A filter bag 340 extends fromthe body frame 330. In this example, the filter bag 340 overlaps one(generally diamond-shaped) circumferential ring of strut elements 332 ofthe body frame 330. In other examples, the filter bag 340 may extendfrom a distal end of the body frame 330 without overlapping the bodyframe 330. In some embodiments, the length of the filter bag 340 is lessthan or equal to one-half of the length of the body frame 330. In someembodiments, the length of the filter bag 340 is greater than one-halfof the length of the body frame 330.

FIG. 4 depicts an example embodiment of a method 400 for thrombectomy.At operation 410 a guidewire can be inserted through a patient'svasculature such that the distal end of the guidewire extends past thetarget thrombus to be treated. In some cases, one or more guidecatheters can be used to assist with the placement of the guidewire. Atoperation 420 an over-the-wire catheter can be inserted over theguidewire. The catheter can be positioned so that its distal tip extendsbeyond the target thrombus to be treated. At operation 430 the guidewirecan be removed through the lumen of the catheter. The catheter canremain in position with its distal tip extending beyond the targetthrombus. At operation 440 a thrombectomy device, such as thrombectomydevice 10 or 300 described above, can be advanced through a lumen of thecatheter. The thrombectomy device, while still in the catheter, can beapproximately positioned so that at least a portion or the entire filterbag is beyond the target thrombus.

In some implementations, the device can be positioned or aligned sothat, on deployment, the body frame of the device will open within thethrombus. For example, a distal edge of the body frame may be alignedlongitudinally with a distal end of the thrombus, so that the filter bagportion of the device may be located distal of the thrombus. In someexamples, the distal end of the body frame may be positioned or alignedslightly distal of the distal end of the thrombus.

At operation 450, while maintaining the position of the thrombectomydevice, the catheter can be withdrawn, causing the thrombectomy deviceto exit the lumen of the catheter. The catheter may be withdrawn, forexample, at least to a point where the proximal portion of the devicebody of the thrombectomy device is outside of the catheter lumen, or toa point where the body frame, tethers, and collar have exited thecatheter lumen.

Since the thrombectomy device can, in some embodiments, beself-expanding, the withdrawal of the catheter can cause thethrombectomy device to expand as a result of being unconstrained fromthe catheter. When the thrombectomy device expands within or adjacent tothe target thrombus, the device can open or expand a blood-flow paththrough or around the target thrombus, based on an outward radialpressure that the body frame of the device may apply against thethrombus when the device expands. If any thrombotic fragments areproduced as a result of the force applied by the expanding of the deviceupon the target thrombus, the thrombotic fragments can be captured inthe filter bag of the thrombus treatment device. The expansion of thethrombectomy device can cause some portions of the target thrombus topenetrate through the body frame of the thrombus treatment device. Theincreased blood flow resulting from operation 450 can enable the bloodto perform natural thrombolysis to potentially reduce the size of thetarget thrombus. If thrombotic fragments are produced they can becollected in the filter bag of the thrombus treatment device.

Operation 460 is an optional act, wherein the collar can be advanced toa position within in internal region defined by the body frame of thethrombectomy device, which can evert the tethers of the device. Thisstep can be taken, for example, for embodiments where the tethers 22deploy in an uneverted configuration so that on deployment the collar 18and the tethers 22 are located proximal of the body frame (see, e.g.,FIGS. 1 and 3). The tethers of the thrombectomy device can thus beeverted and thereby positioned generally within or substantially withinthe interior region of the body frame of the thrombectomy device. Bybringing the collar and all or a portion of the tethers within a regiondefined by the body frame of the device, access possibilities forproviding adjunct therapies or procedures may be enhanced. For example,one or more catheters may be advanced to a location within the bodyframe of the device, and hence to a position of close proximity to thethrombus, which may permit various adjunct therapies or actions thatmight not be possible for devices that cannot evert the tethers in thismanner. In some examples the tethers can be everted so that a portion ofthe tethers extend within a region defined by the filter bag of thethrombus treatment device. As described above, in some implementationsthe tethers can be adapted to deploy in an everted configuration, forexample based on a shape memory property of the tethers.

Whether the collar is positioned in a space interior of the body frameor interior of the filter bag, in some implementations the evertedtethers can be used to sever, shave, or break apart portions of thetarget thrombus that may be protruding through and into the interior ofthe body frame, indicated at optional act 470. The thrombus portions canbe severed, for example, as at least a portion of the tether is causedto move and contact the thrombus portion, whereby the tether may therebycut through the thrombus portion and separate it from the thrombus. Arotational or twisting action may be applied to the support wire of thethrombectomy device, which may impart a twisting force through thecollar to the tethers so that the tethers are twisted or caused to movein a swiveling or pivoting motion while the body frame and filter bagremain generally stationary. Any thrombotic fragments created from themaceration can be collected by the filter bag of the thrombus treatmentdevice.

In some examples, everting the tethers 22, either on deployment orsubsequently by advancing collar 18 to a position within the device, maycause portions of the thrombus to be severed without separatelyimparting a rotational force on the support wire 15. That is, thetethers may act to slice through the thrombus in some embodiments basedon a longitudinal advancement of the support wire and collar, or evenduring deployment, whether they deploy as everted (e.g., beingsubstantially within an area defined by the body frame) or otherwise. Insome examples, the support wire can be repetitively advanced andwithdrawn in a longitudinal direction, one or more times, to severportions of the thrombus.

Operation 480 is an optional act, where the catheter can be moveddistally so that its distal tip is approximately within the interior ofthe body frame. In this position, a lumen of the catheter can be used toaspirate the target thrombus, as by applying a suction force to thelumen from the proximal end of the catheter. The suction force mayaspirate thrombotic material that dislodges from the thrombus as aresult of the suction force, as a result of maceration of the thrombusby the tethers, or as a result of radial force imparted on the thrombusby the body frame of the thrombectomy device. The suction force may alsoaspirate thrombotic material that has collected in the filter bag of thethrombus treatment device. The same or another lumen of the catheter (oranother catheter) can also be used, alternatively or additionally, todeliver one or more thrombolytic pharmacological agents proximately(e.g., from a location interior of a space defined by the thrombus) tothe target thrombus. Again, any thrombotic fragments created from theseactions can be collected by the filter bag of the thrombectomy device.

At operation 490 the thrombectomy device and the catheter can be removedfrom the patient's vasculature. The removal of the thrombectomy devicemay cause the removal of additional portions of the target thrombus,which may collect in the filter bag of the device, or remain attached tothe tethers of body frame. The removal can be performed while applying asuction force to a lumen of the catheter so that any dislodgedthrombotic material may be aspirated, and any remaining material thathas collected in the filter bag can be aspirated. In someimplementations, a proximally directed force may be applied to thesupport wire while holding the catheter in a constant position, and thethrombectomy device may be pulled into a lumen of the catheter. Thethrombectomy device may collapse to the delivery configuration describedpreviously within the lumen of the catheter, and the catheter and devicemay be withdrawn from the body or repositioned at the same or adifferent target thrombus.

FIG. 5A illustrates an example thrombectomy system 500. The thrombectomysystem 500 is generally a system for performing maceration andaspiration of thrombi. This system can be delivered percutaneously andthrough a patient's vasculature to the site of a thrombus, such as aneurovascular, cardiovascular, or peripheral vein thrombus site. Thethrombectomy system 500 may be used in both antegrade and retrogradeapplications.

The example thrombectomy system 500 can generally include astabilization device such as a thrombus displacement device 550, acatheter 540, and a maceration device with two (2) primary components:(i) a tether assembly 520 comprising one or more tethers 522, and (ii) abody frame 530. In some embodiments, the tether assembly 520 and thebody frame 530 can be constructed and configured as the tether assembly20 and the body frame 30 described above in regard to examplethrombectomy device 10. In some embodiments, the body frame 530 caninclude a membranous outer covering that comes into contact with theinner vessel wall. However, generally no filter bag is attached to thebody frame 530.

The thrombus displacement device 550 may be any type of stabilizationdevice that can be used to urge the thrombus 535 toward the macerationdevice, and generally minimize or prevent portions of the thrombus 535from exiting distally of the thrombus displacement device 550. In someimplementations, the thrombus displacement device 550 may be a balloondevice. In other implementations, the thrombus displace device 550 maybe an actuatable braid structure, a filter-like device, a corkscrew-likecoil structure, a basket structure, an occluder disc, a malecot device(e.g., a longitudinally lanced tubular shape which, when axiallycompressed, takes on a fusiform shape as its arms deflect outwardly), orother types of suitable devices.

For simplicity, the discussion that follows will assume a balloon deviceis the thrombus displacement device 550. Thrombus displacement device550 can include a tube 555 and a balloon 560. The tube 555 can convey asuitable inflation medium (e.g., a fluid, gel, gas, solid, foam, etc.)to the balloon 560 to inflate the balloon 560 and can control the axialposition of the balloon 560 within the vessel 510. In some embodiments,the inflation medium includes a contrast media to facilitateradiographical visualization of the balloon 560. The thrombusdisplacement device 550 can be collapsible for delivery via a tube, suchas support tube 515. Alternatively, the thrombus displacement device 550can be delivered by another catheter that may or may not be insertedthrough catheter 540. Although a balloon configuration is describedherein, any suitable stabilization device that can cross at least aportion of the thrombus may be used.

The maceration device, including the tether assembly 520 and the bodyframe 530, is collapsible for delivery via a catheter, such as catheter540. The body frame 530 can be self-expanding as described aboveregarding the body frame 30. The maceration device can further include asupport tube 515 that may be generally analogous to the support wire 15described above. The support tube 515 can be used to push and therebydeploy the collapsed maceration device through its delivery catheter,generally analogous to the manner described above regarding FIGS. 2D-2E.However, in this embodiment the location of the expanded body frame 530can be adjacent to (e.g., located proximally of) the target thrombus,rather than within the thrombus.

The support tube 515 can also be used to evert the tether assembly 520as by advancing a central collar 518 (generally analogous to collar 18described above) to a position within the body frame 530, and can berotated to cause a swiveling or pivoting motion at the tethers 522. Thecentral collar 518 can be used to couple the tether assembly 520 to thesupport tube 515. The maceration device is collapsible so it can becontained within the lumen of catheter 540 for delivery through thepatient's vasculature to the location adjacent to a target thrombus 535.At or near, or, in some embodiments just proximal to the thrombus site,the maceration device can be deployed outwardly from the distal tip ofthe delivery catheter 540, at which time the maceration device canexpand to the unconstrained configuration shown in FIG. 5A. The radialforce of the self-expanding body frame 530 can effectively anchor(temporarily) the body frame 530 to the interior wall of vessel 510 viaan interference fit.

While FIG. 5A depicts a particular maceration device embodiment havingthe distal ends of the tethers 522 coupled to the proximal end of thebody frame 530 and the proximal ends of the tethers 522 coupled to acollar 518 that is coupled to a support tube 515, in another embodimentthe distal ends of the tethers 522 can be coupled with the distal end ofthe body frame 530.

Some embodiments can include two sets of tethers, one set extending fromthe proximal end of the body frame 530 (as shown in FIG. 5A) and thesecond set extending from the distal end of the body frame 530 (notshown). Some embodiments including two sets of tethers can include asingle support tube 515 which can include two collars for coupling thetwo sets of tethers to the support tube 515, in some examples. In thisexample, rotation of the support wire may cause both sets of tethers tobe moved (e.g., in a swiveling or pivoting motion), for example, andeach set of tethers may assist in severing, shaving, or breaking up thethrombus.

Some embodiments that include two sets of tethers can include twosupport tubes located coaxial to each other, where one set of tethersmay be coupled with a first support tube (e.g., by a first collar), andthe second set of tethers may be coupled with a second support tube(e.g., by a second collar). In this example, one or both of the supporttubes may be rotated, or counter-rotated with respect to each other tocause movement (e.g., in a swiveling or pivoting motion) of theassociated sets of tethers for severing, shaving, or breaking up thethrombus, for example. For example, if a single support tube is rotatedand the other support tube is not rotated, the set of tetherscorresponding to the rotated support tube may be caused to move (e.g.,in a swiveling or pivoting motion), while the set of tetherscorresponding to the non-rotated support tube may remain stationary. Inthis example, the interaction of the tethers may cause severing,shaving, or breaking up the thrombus.

In some examples, each of the first set and the second set of tethers iseverted. In some examples, the proximal set of tethers is caused toswivel or pivot while the distal set of tethers remains stationary. Insome examples, the distal set of tethers is caused to swivel or pivotwhile the proximal set of tethers remains stationary. In some examples,both the distal set of tethers and the proximal set of tethers arecaused to rotate or pivot, and in these examples the tether sets may becaused to swivel or pivot in the same direction, or in oppositedirections, for example. In general, rotation of the support tube ortubes may be done similarly to the rotation of support wire 15, asdescribed above. Since the support tubes provide a through-lumen,guidewires and/or thrombus stabilization devices can be inserted andremoved as necessary prior to and during the procedure.

FIG. 5B illustrates the example thrombectomy system 500 wherein thetether assembly 520 has been everted, either by advancing the collar 518to a position interior of the frame 530 or on deployment based on ashape memory property of the tethers 522, to a maceration configuration.In the maceration configuration, the tether assembly 520 can besubstantially located within the interior of the body frame 530. Thisconfiguration is the result of pushing the support tube 515 forward(distally) within the catheter 540 or in conjunction with the catheter540, which causes advancement of the collar 518 and the distal ends ofthe tethers. The flexibility of the tethers 522 can allow the tetherassembly 520 to become everted. The body frame may 530 remain stationarywith respect to the vessel 510 during the movement of the support tube515 and tether assembly 520 to the maceration configuration. That is,the body frame 530 may not experience substantial movement in arotational, linear translational, or any other types of movements. Inthe alternative embodiments having the tethers attached to both ends,the tethers at the distal end of the body frame 530 could be everted byapplying tension to their corresponding support tube. Moreover, in someembodiments, tension can be applied to the distal most support tubewhile simultaneously moving the proximal-most support tube forward,thereby everting both sets of tethers.

FIGS. 5C-5E illustrate end views (as depicted by view “A-A” in FIG. 5B)of the tethers 522 within the body frame 530. In general, these three(3) views depict the articulation and/or manipulation of support tube515 by inducing a swiveling or pivoting action of the tethers 522 duringthe maceration process. As described below, in some embodiments theswiveling movements of the tethers 522 can sever, shave, or break apartportions of the thrombus 535 for removal by aspiration by catheter 540.In some implementations, FIGS. 5C-5E depict views of the tethers 22 ofthe thrombectomy device 10 described at FIG. 1 and at FIG. 2G.

FIG. 5C depicts an example configuration of the tethers 522 in theirneutral position or generally relaxed condition. As can be seen in FIG.5C, in some embodiments the tethers 522 can have a generally loopedshape in the neutral position. In some examples, the tethers 522 mayhave a generally “S” shape in the neutral position.

FIG. 5D depicts an example configuration, which may represent a firsttorqued position, of the one or more tethers 522 after the support tube515 has been rotated in the clockwise direction as indicated by arrow570. As can be seen in FIG. 5E, the tethers 522 generally have a firstlinear shape in the first torqued position. FIG. 5E depicts an exampleconfiguration, which may represent a second torqued position, of thetethers 522 after the support tube 515 has been rotated in thecounterclockwise direction as indicated by arrow 575. As can be seen inFIG. 5E, the tethers 522 generally have a second linear shape in thesecond torqued position.

The maceration action of the one or more tethers 522 on the thrombus 535can be created, in some implementations, by rotating support tube 515clockwise and counterclockwise (back and forth, repeating as desired).In this manner, the tethers 522 may transition from their configurationin FIG. 5D to FIG. 5E, and back again to FIG. 5D, and then again to FIG.5E, and so on. In other cases, a single rotation (or no rotation, i.e.,solely a longitudinal motion to thereby articulate and/or manipulate thesupport tube 515) may be enough for the tethers 522 to adequatelymacerate the thrombus to the extent determined necessary by theclinician operator. In some implementations, the rotation of the supporttube 515 can be limited by having, for example, hard-stops to preventrotation beyond that which the tethers 522 are capable of handlingwithout imparting forces on the body frame 530 which could otherwisecause movement of the body frame 530 in relation to vessel 510, inmanners similar to those discussed above with reference to device 10. Insome embodiments, the tethers 522 can sweep through a range of motion ofup to 180 degrees without causing a substantial rotational orlongitudinally translational motion of the body frame 530 in relation tovessel 510. In some embodiments, the tethers 522 can sweep through arange of motion of up to 270 degrees without causing a substantialrotational or longitudinally translational substantial motion to thebody frame 530 in relation to vessel 510. In some embodiments, thetethers 522 can sweep through a range of motion of up to 360 degreeswithout causing a substantial rotational or longitudinally translationalmotion of the body frame 530 in relation to vessel 510. In someembodiments, the tethers 522 can sweep through a range of motion of upto 540 degrees without causing a substantial rotational orlongitudinally translational motion of the body frame 530 in relation tovessel 510. In some embodiments, the tethers 522 can sweep through arange of motion of equal to or greater than 540 degrees without causinga substantial rotational or longitudinally translational motion of thebody frame 530 in relation to vessel 510.

FIG. 5F illustrates the maceration process of example thrombectomysystem 500. The maceration process is generally performed by theswiveling of the one or more tethers 522 that may contact portions ofthe thrombus 535 to cut portions of the thrombus 535 into thrombusfragments 535′ which can be aspirated by catheter 540. The swivelingmotion of the tethers 522 that may cause the tethers 522 to act ascutting blades has been described above in regard to FIGS. 5B-5E. Insome embodiments, the swiveling tethers 522 can come into contact withthrombus 535 by the urging of the balloon 560 on the thrombus 535. Thatis, the thrombus displacement device 550, which may be attached to asupport wire, can be pulled by a clinician operator to force thethrombus 535 into the interior of the body frame 530 and into contactwith the tethers 522 as they are being swiveled. In this manner,portions of the thrombus 535 can be severed into thrombus fragments535′. In other embodiments, the stabilization device can remainstationary and the masceration device can be advanced towards thethrombus 535 to perform masceration of the thrombus 535.

The one or more thrombus fragments 535′ can be removed from the vessel510 by an aspiration device, such as catheter 540 or another aspirationdevice. Catheter 540 may also be the delivery catheter for thrombectomysystem 500. The maceration process can continue by gradually pulling thethrombus displacement device 550 while motioning tethers 522 (e.g., byrotating tube 515). These operations can be performed manually or withthe assistance of mechanical or electro-mechanical devices. Dependingupon the consistency of the thrombus, the act of pulling and forcing thethrombus through the tethers may be enough to sever the thrombus intoaspiratable-sized portions without causing motion of the tethers. Thatis, in some cases when the thrombus is soft enough, the tethers may notneed actuation to sever and aspirate the thrombus.

While the maceration is taking place, the wall of vessel 510 may beprotected from potential trauma from the tethers 522 because of thepresence of the body frame 530. The body frame 530 acts as a protectivebarrier between the tethers 522 and the inner wall of vessel 510. Thebody frame 530 of some embodiments may also include a covering (notshown) such as an ePTFE tubular covering which could also assist inprotecting the host vessel from undue trauma during the macerationprocess. Also, because of the lengths of the individual tethers 522,which, in some embodiments, may have lengths at least about two times adiameter of an opening defined by the body frame 530 in an unconstrainedstate, the rotational force applied to the support tube 515, and throughthe collar 518 to the tethers 522, may substantially dissipate over thelength of the tethers so that only a minimal force or substantially zeroforce is transmitted to the body frame 530 of the device. In thismanner, damage to the vessel wall may be minimized because the bodyframe may not rotate or move as the support tube 515 is rotated, forexample.

At the completion of the maceration process, the rotation of the supporttube 515 and the linear motion of the thrombus displacement device 550can be ceased. Prior to removal of the thrombectomy system 500 fromvessel 510, the maceration device can be retracted within the catheter540. Also, the balloon 560 can be deflated and retracted back throughthe lumen provided by the support tube 515. The thrombectomy system 500can then be removed from the patient's vasculature.

FIG. 6A illustrates an example thrombectomy device 600. This device canbe delivered percutaneously and through a patient's vasculature to thesite of a thrombus, such as a neurovascular, cardiovascular, orperipheral vein thrombus site. The thrombectomy device 600 may be usedin both antegrade and retrograde applications.

The example thrombectomy device 600 is generally a device for treating atarget thrombus by opening or enlarging a blood-flow path through thethrombus, enabling natural thrombolysis via increased blood flow, andperforming maceration of a thrombus while capturing thromboemboli in afilter bag. In general, the thrombectomy device 600 includes a bodyframe 630, a filter bag 640, and a tether assembly with two primarycomponents: (i) tethers 625 and (ii) tether frame 620. The body frame630, filter bag 640, delivery catheter 610, and support wire 655 areanalogous to their corresponding components as described above. However,the tether assembly of thrombectomy device 600 can have a differentarrangement as compared to previously described embodiments.

In some embodiments, the tether frame 620 can have multiple individualelongate arms that are each attached at one of their ends to a centralhub 618. The central hub 618 can serve to couple the tether frame 620 tothe support wire 655. The individual arms of tether frame 620 can extendradially from the central hub 618 in a manner analogous to, for example,the spokes of a wheel. In some examples, the individual arms of thetether frame 620 may extend from the hub 618 without crossing oroverlapping one another. In some examples, the individual arms mayextend from the hub 618 and may cross or overlap one or more of theother arms, analogous to spokes of a bicycle wheel, for example.

The opposite ends of the individual arms can be attached to individualtethers 625. In some embodiments, the number of individual armscorresponds with the number of individual tethers as required for theparticular configuration of the body frame 630 of the thrombectomydevice 600. The tether frame 620 can be constructed from materials suchas nitinol, titanium, stainless steel, various polymers, or acombination or sub-combination of materials.

The tethers 625 can be attached on their proximal ends (as shown in FIG.6A) to the tether frame 620 and at their distal ends to the frame body630. The tethers 625 can be, for example, thin flexible members with lowcolumn strengths. For example, the tethers 625 can be in the form ofwires, fibers, filaments, membranes, strings, and/or threads. Thetethers 625 can be constructed from various materials such as PTFE,other polymers, or from metals such as nitinol, titanium, and stainlesssteel, or a combination or sub-combination of materials.

The thrombectomy device 600 can be delivered to the site of a targetthrombus 650 within the lumen of a catheter 610. The thrombectomy device600 can be deployed from the catheter 610 such that the frame body 630engages with the target thrombus 650. As described above with referenceto frame body 30, the frame body 630 can act on the thrombus 650 to openor enlarge a blood-flow path. With increased blood flow, the naturallytic action of blood flow on the thrombus 650 can be enhanced to reducethe thrombus 650. Particles of dislodged thrombotic material can becaptured in the filter bag 640 to prevent thromboemboli from beingreleased into the vasculature.

FIG. 6B illustrates the example thrombectomy device 600 arranged in amasceration configuration. The thrombectomy device 600 can be arrangedin the masceration configuration, for example, by advancing the supportwire 655 distally, as represented by arrow 617. As the support wire 655is pushed distally, the hub 618 and tether frame 620 are similarlyadvanced distally, while the body frame 630 remains in a substantiallystationary position (e.g., no substantial rotational or translationalmovements) with respect to the vessel, allowing the tether frame 620 tobe moved into the interior region of body frame 630.

In some embodiments, the diameter of the tether frame 620 can be smallerthan the inner diameter of the body frame 630 so that the tether frame620 can fit inside of the body frame 630. As the tether frame 620 movesinto the interior of the body frame 630, the tethers 625, due to theirflexibility, can be pulled along by the movement of the tether frame620. In this manner, the tether frame 620 and the tethers 625 can bepositioned within the interior of the body frame 630. Further, thetethers 625 can be positioned substantially parallel and adjacent to theinner wall of the body frame 630 in preparation for masceration of thethrombus 650.

The thrombus masceration process can be performed by rotating thesupport wire 655 as indicated by arrows 616. The motion imparted by thesupport wire 655 to the tethers 625 can cause the tethers 625 to act asthrombus shearing arms or blades. The clinician operation can actuate,manually or with device assistance, a rotary action of the support wire655 in a manner similar to description above in regard to FIGS. 5B-5E.In some implementations, the rotation of the support wire 655 can belimited by having, for example, hard-stops to prevent rotation beyondthat which the tethers 625 are capable of handling without impartingforces on the body frame 630 which could otherwise cause movement of thebody frame 630. The body frame 630 can protect the vessel wall frompotential trauma from the masceration process. Particles of dislodgedthrombotic material can be captured in the filter bag 640 to preventthromboemboli from being released into the vasculature.

FIG. 7 illustrates an example thrombectomy device 700. This device canbe delivered percutaneously and through a patient's vasculature to thesite of a thrombus, such as a neurovascular, cardiovascular, orperipheral vein thrombus site. The thrombectomy device 700 may be usedin both antegrade and retrograde applications. The thrombectomy device700 is generally a device for treating a target thrombus by opening orenlarging a blood-flow path, enabling natural thrombolysis via increasedblood flow, and performing maceration of a thrombus while capturingthromboemboli in a filter bag.

In general, the example thrombectomy device 700 includes a body frame735, a filter bag 740, a support tube 755, and tethers 715. The bodyframe 735 and filter bag 740 are analogous to their correspondingcomponents as described above. However, the tethers 715 and the supporttube 755 of thrombectomy device 700 can have a different arrangement ascompared to previously described embodiments.

The tethers 715 can be flexible strings, wires, threads, fibers, or thelike, and made from a polymeric material such as PTFE, nylon, orpolyester, or from a metallic material such as nitinol. The proximalends of the tethers 715 can be arranged so that they are accessible tobe controlled by a clinician operator, as shown at the left side of FIG.7, where they may exit a lumen of the tube 755. The tethers 715 can berouted through the lumen of the support tube 755. The tethers 715 canexit the support tube 755 near the central collar 718 and be routedapproximately radially outward and through the body frame 735 structurenear the distal end of the body frame 735. From there (the distal end ofthe body frame 735), the tethers 715 can be routed proximally towardsthe proximal end of the body frame 735. For example, the tethers 715 canbe woven among the structural members of the body frame 735 as thetethers 715 are routed towards the proximal end of the body frame 735.In some examples, the tethers 715 may be wound through cells of the bodyframe 735 as the tethers are routed from the distal end of the bodyframe to the proximal end of the body frame. In some examples, and asshown in FIG. 7, the tethers 715 can be routed from near the distal endof the body frame 735 to the proximal end of the body frame outside ofthe body frame (e.g., generally outside of a space defined by the bodyframe 735).

In some embodiments, when the routing of the tethers 715 reaches theproximal end of the body frame 735, the individual tethers 715 can berouted around the proximal circumference of the body frame 735—so thateach individual tether 715 makes a loop or “lasso” around the proximalcircumference of the body frame 735. The individual tethers 715 can thenbe attached to the body frame 735 (e.g., slip knots can be used). Whenthe tethers 715 are pulled in a proximal direction at their proximalends (e.g., by an operator), the distal and proximal ends of the bodyframe 735 can be deflected or collapsed inward towards the support tube755. In this manner, a clinician operator can enable recapture of thethrombectomy device 700. That is, applying tension to the tethers 715,manually or with a device, can collapse the profile of the distal andproximal ends of the body frame 735 so that it can more easily enterwithin the lumen of a catheter (not shown in FIG. 7).

In some embodiments, when the routing of the tethers 715 reaches theproximal end of the body frame 735, the individual tethers 715 can makea partial loop around the proximal end of the body frame 735. Forexample, for a tether arriving at the proximal end of the body framenear a particular cell of the body frame, the tether may be routedcircumferentially around the proximal end of the body frame and attachedto a support member of an adjacent cell of the body frame. Theindividual tethers 715 can then be tied to the body frame 735 inlocations on the body frame 735 so that the individual tethers 715cooperatively form one single loop, or lasso, around the circumferenceof the proximal end of the body frame 735.

In some examples, collar 718 may be omitted. For example, the tethers715 may exit a distal end of the tube 755. As another example, the tube755 may include apertures (e.g., one aperture for each tether) in a sidewall of the tube 755 near a distal end of the tube, and the tetherscould exit the tube via the apertures.

As illustrated by example thrombectomy device 700, the tethers of thethrombectomy devices provided herein can extend from various locationson the body frames. In most of the example thrombectomy devices providedherein, the tethers are depicted as extending from the proximal end ofthe body frame. However, it should be understood that the tethers canextend from various other locations on the body frame. For example, insome embodiments, the tethers extend from the distal end of the bodyframe. In some embodiments, the tethers extend from a location betweenthe proximal and distal ends of the body frame. In some embodiments, theindividual tethers of a single thrombectomy device extend from differentlocations on the body frame, such as from the proximal end, distal end,or locations between the proximal and distal ends.

FIG. 8 depicts an example embodiment of a method 800 for thrombolysis.In general, this method can be used to enhance the effectiveness of apharmacological thrombolytic agent that can be delivered to a targetthrombus. At operation 810 the filter bag of a thrombectomy device(e.g., device 10, 300, 600, or 700) can be treated with autologous bloodor a thrombogenic material to “pre-clot” the filter media, i.e., to makethe filter bag temporarily occlusive to blood flow. For example, in someimplementations the filter bag can be soaked in autologous blood, or astagnant thrombogenic solution or gelatin, prior to deployment so thatthe blood or other material clots within the small holes of the filterbag. In some implementations, autologous blood or thrombogenic materialcan be aspirated into the delivery catheter to make it come in contactwith a filter bag that is within the delivery catheter. In someimplementations, autologous blood or thrombogenic material can beinjected through a catheter to make it come in contact with an in situfilter bag that has been deployed in a vessel. The device receiving thepre-clotting treatment can be any thrombectomy device that uses a filterbag, including but not limited to the thrombectomy devices describedabove.

At operation 820 the device can be delivered to and deployed at thetarget thrombus site. As described above, the device may be deployed sothat the (pretreated) filter bag is positioned distally of the targetthrombus (e.g., distally of and adjacent to the thrombus). At operation830 a pharmacological thrombolytic agent can be delivered to the targetthrombus. For example, the thrombolytic agent (e.g., tPA) can beinjected to the bloodstream area of the target thrombus via a catheteror hypotube. In some embodiments, the catheter used to deliver thethrombectomy device can also be used to deliver the thrombolytic agent.Or, the lumen of the delivery catheter can be used to route anadditional drug delivery tube to the site of the target thrombus. Insome implementations, the thrombolytic agent can be delivered via acatheter that is advanced so that the distal end of the catheter isinterior of the body frame of the device, thereby releasing thethrombolytic agent within a space defined by the clot itself when thebody frame is positioned within the clot.

Because the pretreated filter bag may act as a temporary occluder,restricting blood flow through the device, the administered thrombolyticagent may remain concentrated at or near the thrombus site, which mayenhance the action of the thrombolytic agent in dissolving the thrombus,and may prevent the thrombolytic agent from dispersing systemically intothe vasculature of the patient for a period of time.

At operation 840, the thrombectomy device can be removed, for exampleafter waiting a predetermined time. The filter bag, having beenpretreated to make it more occlusive to blood flow, can cause thethrombolytic agent delivered to the target thrombus to dwell in the areaof the target thrombus—rather than being promptly flushed away by bloodflow. That additional dwell time of the thrombolytic agent in the areaof the target thrombus can enhance the effectiveness of the thrombolyticagent's thrombolytic action on the target thrombus. Hence, operation 840prescribes waiting a predetermined time. Eventually the thrombolyticagent, which can also act to deplete the thrombogenic material on thepretreated filter bag, may substantially dissolve the thrombogenicmaterial on the filter bag. That is, while the thrombolytic agent isdwelling in the target thrombus area, the thrombolytic agent can alsoact on the thrombogenic material on the filter bag in addition to actingon the target thrombus. In this manner the occlusive properties of thethrombogenic material on the filter bag may be diminished with time, andblood flow through the filter bag may commensurately increase, which mayreestablish perfusion of the downstream vasculature. Because of the timeit takes for the thrombolytic agent to dissolve the thrombogenicmaterial on the filter bag, the thrombolytic agent may have more of anopportunity to dissolve the target thrombus.

FIG. 9 illustrates an example embodiment of a thrombectomy device 900.This device can be delivered percutaneously and through a patient'svasculature to the site of a thrombus, such as a neurovascular,cardiovascular, or peripheral vein thrombus site. The thrombectomydevice 900 may be used in both antegrade and retrograde applications.

The example thrombectomy device 900 generally includes a support wire915 and a device body 912 including four (4) primary components: (i) aproximal tether assembly 920, (ii) a body frame 930, (iii) a distaltether assembly 926, and (iv) a filter bag 940 (shown in across-sectional view to enable visualization of the distal tetherassembly 926 that is located within the internal space defined by thefilter bag 940).

A proximal central collar 918 can couple the proximal tether assembly920 to the support wire 915. A distal central collar 919 can couple thedistal tether assembly 926 to the support wire 915. The support wire 915extends at least between the proximal central collar 918 and the distalcentral collar 919. In some embodiments, the support wire 915 extendsdistally beyond the distal central collar 919.

In some embodiments one or both central collars 918 and 919 are movablycoupled to the support wire 915. In some embodiments, making one or bothcentral collars 918 and 919 movably coupled to the support wire 915 canfacilitate collapsibility of the device 900 for deploying the device 900via a delivery catheter. In some embodiments, making one or both centralcollars 918 and 919 movably coupled to the support wire 915 canfacilitate eversion of the tether assemblies 920 and 926 for thrombusmaceration processes. In some such embodiments, the proximal centralcollar 918 is fixedly coupled to the support wire 915 and the distalcentral collar 919 is movably coupled to the support wire 915. In somesuch embodiments, the proximal central collar 918 is movably coupled tothe support wire 915 and the distal central collar 919 is fixedlycoupled to the support wire 915. In some such embodiments, the proximalcentral collar 918 is movably coupled to the support wire 915 and thedistal central collar 919 is movably coupled to the support wire 915. Insome such embodiments, the proximal central collar 918 is fixedlycoupled to the support wire 915 and the distal central collar 919 isfixedly coupled to the support wire 915.

In some embodiments, one or more collar stops 916 are included on thesupport wire 915. The collar stops 916 can limit the travel of movablycoupled central collars 918 and 919.

The distal device body 912 is collapsible so it can be contained withina catheter lumen for delivery through the patient's vasculature to thelocation of a thrombus (refer, e.g., to FIGS. 2D and 2E). At thethrombus site, the thrombectomy device 900 can be deployed outwardlyfrom the distal tip of the delivery catheter, at which time thethrombectomy device 900 can expand to the unconstrained configurationshown in FIG. 9.

The support wire 915 can include a solid or hollow support wire, or caninclude any other tubular article with at least one continuous lumenrunning therethrough (as described above in reference to support wire15). In some embodiments, support wire 915 extends through the distalend of the filter bag 940 to become the most distal component of thethrombectomy device 900. In some embodiments, support wire 915 extendsinto the distal device body 912 but not through the distal end of thefilter bag 940. In some embodiments, support wire 915 extending distallyfrom at least the body frame 930 can also include one or more balloondevices disposed near the distal end.

The tether assemblies 920 and 926 of the thrombectomy device 900 includeone or more tethers 922 and 924 respectively. The one or more tethers922 and 924 are generally elongate elements (as described above inreference to tethers 22) that can be coupled on one end with the supportwire 915 (using one or more collars, such as central collars 918 and919). The tethers 922 and 924 can be coupled with the body frame 930 atthe tether's 922 and 924 opposite end. In some embodiments, the proximaltethers 922 extend from the support wire 915 to the proximal end of thebody frame 930. In some embodiments, the distal tethers 924 extend fromthe support wire 915 to the distal end of the body frame 930. In someembodiments, the tethers 922 and 924 extend from the support wire 915 tolocations on the body frame 930 between the proximal and distal ends ofthe body frame 930 (not shown). While in some embodiments just oneproximal tether 922 is included, some embodiments include two, three,four, or more proximal tethers 922. While in some embodiments just onedistal tether 924 is included, some embodiments include two, three,four, or more distal tethers 924.

The length of the tethers 922 and 924 can be determined in accordancewith the operational characteristics desired. For example, in someapplications a short deployment length is desired, leading to aselection of short or looped support strut tethers 922 and 924. In someapplications the ability to evert the tethers 922 and 924 within thebody frame 930 or filter bag 940 leads to a selection of using longertethers 922 and 924, which may also be looped in some examples.

In some embodiments, the tethers 922 and 924 are substantially the samelength. In some embodiments, the proximal tethers 922 and the distaltethers 924 have dissimilar lengths. In some embodiments, the tethers922 and 924 are of substantially equal cross-sectional size and/orshape. In some embodiments, the proximal tethers 922 and the distaltethers 924 have dissimilar cross-sectional sizes and/or shapes incomparison to one another.

In some embodiments, all the proximal tethers 922 are of substantiallyequal length. In some embodiments, one or more proximal tethers 922 areunequal in length in comparison to one or more other proximal tethers922. In some embodiments, all the proximal tethers 922 are ofsubstantially equal cross-sectional size and/or shape. In someembodiments, one or more proximal tethers 922 are unequal incross-sectional size and/or shape in comparison to one or more otherproximal tethers 922.

In some embodiments, all the distal tethers 924 are of substantiallyequal length. In some embodiments, one or more distal tethers 924 areunequal in length in comparison to one or more other distal tethers 924.In some embodiments, all the distal tethers 924 are of substantiallyequal cross-sectional size and/or shape. In some embodiments, one ormore distal tethers 924 are unequal in cross-sectional size and/or shapein comparison to one or more other distal tethers 924.

The tethers 922 and 924 can serve multiple purposes. For example, onepurpose of the tethers 922 and 924 can be to couple the distal devicebody 912 of the thrombectomy device 900 to the support wire 915. Anotherpurpose of the tethers 922 and 924 can be to enable flexible compliancebetween the body frame 930 and the contours of irregularly shapedthrombi or vessel walls. Another purpose can be to provide supplementalradial force between the body frame 930 and a thrombus so as torecanalize or maintain a blood-flow path. Another purpose (as describedfurther above, e.g., FIGS. 2G and 2H) can be to sever, shave, or breakup thrombi by everting and causing a pivoting motion (or linear motion)of the tethers 922 and 924 as a part of a thrombectomy procedure. Insome implementations, the tethers 922 and 924 need not be everted tosever, shave, or break up thrombi and participate in the thrombectomyprocedure. In some implementations, the tethers 922 and 924 may becoated with an abrasive material, which may aid the tethers in severing,shaving, or breaking up thrombi when pivotal motion is applied to thetethers 922 and 924. In some implementations, a portion of the tethersmay be sharpened, which may aid the tethers in severing, shaving, orbreaking up thrombi when pivotal motion is applied to the tethers 922and 924.

The body frame 930 can be generally analogous to the body frame 930(e.g., in reference to FIG. 1). In general, embodiments of theself-expanding body frame 930 can provide a substantial radial force,while exhibiting a minimal lateral resistance to being collapsed to alow profile for placement in a delivery catheter. The radial force canbe used to recanalize or maintain a blood-flow path through or around athrombus. The minimal lateral resistance to being collapsed is usefulfor positioning and repositioning the body frame 930 within the smalldiameter of a delivery catheter. Interstices in the body frame 930provide open spaces between the strut elements 932 that can allow forportions of a thrombus to protrude within the interior of the body frame930. Portions of thrombus in the interior of the body frame 930 can beremoved by, for example, aspiration or maceration (as described above).In some embodiments, the ratio of the length of the body frame 930 tothe outer diameter of the body frame 930 in an expanded andunconstrained state is about 1:1, about 2:1, about 3:1, about 4:1, about5:1, about 6:1, about 7:1, about 8:1, or more than about 8:1.

The filter bag 940 can be generally analogous to the filter bag 940(e.g., in reference to FIG. 1). In general, filter bag 940 can captureand contain thromboemboli, plaque, and other particulate, while enablingpass-through flow of blood. The filter bag 940 can be made from avariety of filter media materials. For example, the filter media can bea laser perforated layer of thin polytetrafluoroethylene (PTFE). In someembodiments, the range of pore sizes of the filter media can be from20-30 μm, 30-50 μm, 50-70 μm, 70-80 μm, or 80-100 μm.

In some embodiments, the longitudinal length of the filter bag 940 isapproximately proportionate to the length of the body frame 930. Forexample, in some embodiments the length of the filter bag 940 is lessthan or equal to about one-half of the length of the body frame 930. Insome embodiments, the length of the filter bag 940 is about one-half ofthe length of the body frame 930 to about equal to the length of thebody frame 930. In some embodiments, the length of the filter bag 940 isgreater than the length of the body frame 930.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinvention or of what may be claimed, but rather as descriptions offeatures that may be specific to particular embodiments of particularinventions. Certain features that are described in this specification inthe context of separate embodiments can also be implemented incombination in a single embodiment. Conversely, various features thatare described in the context of a single embodiment can also beimplemented in multiple embodiments separately or in any suitablesubcombination. Moreover, although features may be described above asacting in certain combinations and even initially claimed as such, oneor more features from a claimed combination can in some cases be excisedfrom the combination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various assemblies andcomponents in the embodiments described above should not be understoodas requiring such separation in all embodiments, and it should beunderstood that the described components and systems can generally beintegrated together in a single product or into multiple products.

Particular embodiments of the subject matter have been described. Otherembodiments are within the scope of the following claims. For example,the actions recited in the claims can be performed in a different orderand still achieve desirable results. As one example, the processesdepicted in the accompanying figures do not necessarily require theparticular order shown, or sequential order, to achieve desirableresults. In certain implementations, multitasking and parallelprocessing may be advantageous.

What is claimed is:
 1. A thrombus treatment device, comprising: asupport wire; a body frame portion that is disposed about an axisdefined by the support wire, wherein a longitudinal length of the bodyframe portion is at least two times as long as an outer diameter of thebody frame portion; a tether portion that includes one or more tethersthat extend from the body frame portion to a collar that is coupled tothe support wire, the collar being configured to be advanced toward afilter portion; and wherein the filter portion that extends from thebody frame portion.
 2. The device of claim 1, wherein the longitudinallength of the body frame portion is at least three times as long as theouter diameter of the body frame portion.
 3. The device of claim 1,wherein the longitudinal length of the body frame portion is at leastfour times as long as the outer diameter of the body frame portion. 4.The device of claim 1, wherein the longitudinal length of the body frameportion is at least five times as long as the outer diameter of the bodyframe portion.
 5. The device of claim 1, wherein a longitudinal lengthof the filter portion is less than or equal to one-half of thelongitudinal length of the body frame portion.
 6. The device of claim 1,wherein the one or more tethers are adapted to evert to a configurationwherein the one or more tethers are substantially within an area definedby the body frame portion.
 7. The device of claim 1, wherein the one ormore tethers are comprised of nitinol.
 8. The device of claim 1, whereinthe one or more tethers are comprised of a polymeric material.
 9. Thedevice of claim 1, wherein the device includes multiple tethers thateach extend from the body frame portion to the collar that is coupled tothe support wire.
 10. The device of claim 9, wherein each tether of themultiple tethers is adapted to evert to a configuration wherein eachtether of the multiple tethers is substantially within an area definedby the body frame portion.
 11. The device of claim 1, wherein the filterportion does not substantially overlap the body frame portion.
 12. Thedevice of claim 1, wherein the body frame portion defines a plurality ofopen-faced cells arranged in at least three rows along the longitudinallength of the body frame portion, and wherein the filter portionoverlaps the body frame portion by up to one row of the at least threerows and does not overlap the remaining body frame portion.
 13. Thedevice of claim 12, wherein the body frame portion defines from three toten rows of open-faced cells along the longitudinal length of the bodyframe portion.
 14. The device of claim 1, wherein the filter portionoverlaps 20% or less of the longitudinal length of the body frameportion.
 15. The device of claim 1, wherein the one or more tethersextend from a proximal end of the body frame portion, and wherein thefilter portion extends from a distal end of the body frame portion. 16.A thrombus treatment device, comprising: a support wire; a body frameportion that is disposed about an axis defined by the support wire,wherein a longitudinal length of the body frame portion is at least twotimes as long as an outer diameter of the body frame portion, whereinthe body frame portion defines a plurality of open-faced cells arrangedin at least three rows along the longitudinal length of the body frameportion, and wherein the filter portion overlaps the body frame portionby up to one row of the at least three rows and does not overlap theremaining body frame portion, and wherein the body frame portion definesfrom three to ten rows of open-faced cells along the longitudinal lengthof the body frame portion; a tether portion that includes one or moretethers that extend from the body frame portion to a collar that iscoupled to the support wire; and a filter portion that extends from thebody frame portion.